The architecture of the second half of the sixteenth century in Milan developed, here as elsewhere, on several lines and styles that can be summarized in mannerism, counter-reformed art and classicism. These currents divided the urban art scene often undergoing mutual contamination.
The Milanese scene of the second half of the sixteenth century must therefore be analyzed considering the particular position of the city: if for the Spanish Empire it represented a strategic military outpost, from the religious point of view it was at the center of the conflict between the Catholic Church and the Reformed Church. Consequently the greatest contribution was given by religious art in the face of a lower artistic and architectural civil production.
If, in adopting the mannerist style, the clients and the urban artists had as their reference experiences of Central-Italian derivation, the position of the city near the Protestant Switzerland made Milan one of the main centers of flowering and elaboration of counter-reformed art, thanks to the capillary action of St. Charles Borromeo .
The Instructiones by Carlo Borromeo
With the advent of the Council of Trent and the Counter-Reformed Church, the ecclesiastical authorities exploited art as a means of spreading the new doctrines in contrast to Protestantism and other heresies; the art was then subjected to strict rules and controls, so that the artists depicted episodes of the most original biblical tradition. Since the requirements for architecture alone were not very stringent, Cardinal Carlo Borromeo, among the protagonists of the Council of Trent, wrote the Instructiones fabricae et suppellectilis ecclesiasticae, or an architectural compendium that regulates the construction of new churches. These provisions led the development of religious buildings in the following years until they were also applied in Latin America, then part of the Spanish Empire. As indicated by the decrees of the Council, a rich and monumental art should have impressed the faithful, pushing them to contemplation and learning of religious doctrine: the representations, although grandiose and solemn, would have been of simple understanding even by the uneducated people. The thing was obviously contrary to the Protestant doctrine, which considered the excessive and pompous decorations as a distraction for the faithful or even a heresy.
The Borromeo debuts in Instructiones talking about the location of the church, which must possibly be in an elevated position and away from noises or noisy places, and detached from other houses except the residence of the priest or bishop. The number of steps to reach this position must be odd. It also provides information on the size of the church, which must be large enough to accommodate the faithful for special occasions. Among the most important details is the shape from the plant, so the Borromeo recommends the use of the Latin cross to the detriment of the central plant: although used in many illustrious cases, especially in the Renaissance, the Borromeo considered the central plant a reference to the temples pagans and used less in Christian architecture, while the Latin cross was justified by the supremacy of the first basilicas that used this form.
The Tuscan Domenico Giunti and the Perugino Galeazzo Alessi were the first architects to break away from the Lombard late-Renaissance tradition. At first you have the churches of San Paolo Converso and Sant’Angelo, set according to the same design concept with a single nave and side chapels with coverage barrel vault, quote of ‘ Alberti’s Basilica di Sant’Andrea already found in the church of Santa Maria at San Satiro Bramante.
The church of San Paolo Converso, a sometimes contested attribution, was begun in 1549 to be in an advanced state two years later; the façade dates back to the early seventeenth century, but is heavily influenced by Tibaldi’s Milanese works and was designed taking into account the decoration and monumentality according to the Instructiones del Borromeo. The interior was decorated largely by the Campi brothers and is among the most representative of the Milanese second half of the sixteenth century: more than the decorations of the six chapels along the nave and the partition between the hall and the environment for the cloistered nuns, It is noteworthy the large fresco on the vault ofVincenzo Campi of the Ascension of Christ, great proof of late Renaissance illusionism in the footsteps of the most famous false choir of Bramante in Santa Maria near San Satiro. Overall, in the pictorial decoration there emerges a certain influence with the Mannerist Center-Italian experience, above all Giulio Romano, while there are some inspirations to the frescoes of the Dome of the Parma Cathedral of Correggio in the perspective of the frescoed vault; finally, the results of the Decollation of St. John the Baptist and the Martyrdom of St. Lawrence by Antonio Campiin the first and third chapel on the right they are sometimes listed in the current of “precaravaggism”.
The church of Sant’Angelo dates back to 1552, when it was completely rebuilt after having demolished the remains of the old church damaged by the wars that took place in the city at that time. The project included the three cloisters of the church, demolished in the twentieth century, which led to the facade dating back to the seventeenth century: originally the Giunti had a façade with rigid proportions, sober and practically without decorations, but never realized. The structure of the church was designed as a Latin cross with a single nave with a barrel vault and a total of sixteen side chapels. In the chapel dedicated to Saint Catherine of Alexandria, the paintings of the Stories of Saint Catherine can be seen on either side(1564) by Antonio Campi, who sets the story in a nocturnal setting often seen in Caravaggio’s settings, in which the Cremonese painter anticipates the luminism used by Merisi; in the chapel of San Gerolamo and the chapel dedicated to the Virgin Mary are Ottavio Semino’s paintings of Mannerist style with Flemish influences, however mitigated by the early post-Tridentine teachings, for which the painter chose scenes of daily life. We always find Ottavio Semino to fresco the head of the transept, while the sacristy is adorned with oil on canvas of the mystic Marriage of Saint Catherine (1579) by Peterzano; it is finally attributed to Annibale Fontanathe tomb of the bishop Pietro Giacomo Malombra.
The first work in Milan by Vincenzo Seregni, excluding the apprenticeship in the Fabbrica del Duomo, was in the reconstruction of the church of San Vittore al Corpo in collaboration with Alessi: the two architects anticipated in the internal structure the counter-shaped architectural canons thanks to longitudinal plant with natural outlet towards the dome space: the internal structure was compared by James Ackerman to the Basilica of San Giorgio Maggiore of Palladio, in which the Venetian architect combined the central plan with the Latin cross plan. To continue with the similarities between the two churches, the original project foresaw a monumental pronao surmounted by a tympanum that resumed the partitions of the facade of San Giorgio. Built starting from 1559 on the remains of the old early Christian basilica of San Vittore, the new church was set in an inverted orientation compared to the previous one, and it was necessary to demolish the imperial mausoleum of Massimianoto finish the work; the works lasted until six hundred years and the façade was never completed according to the original plan. The interior is divided into three naves, the largest has a barrel vault while the two side vaulted vaults decorated with stuccos and frescoes: if the structure retains the sixteenth-century appearance, the decorations are for the most part seventeenth-century. Noteworthy is the late sixteenth century wooden choir with the Stories of St. Benedict based on the fifty engravings of Aliprando Caprioli on the life and miracles of the saint.
Alessi continued its counter-reform program with the construction of the new church of San Barnaba for the Barnabiti fathers, an order recently created to promote the dissemination of the Tridentine doctrine: the internal system with a single nave can be considered one of the first attempts of ” basilica della Riforma “. From a decorated façade, although without the typical late-sixteenth century plasticism, it is entered inside divided into three rooms to allow the monastic life of the order and the prayer of the faithful: the first room is composed of a single nave with barrel vault, so desired to improve the acoustics in the friars’ oratorical meetings with the faithful,and in the square-based choir with cross vault. Among the internal works we find the Pietà by Aurelio Luini in the second right chapel, San Gerolamo by Carlo Urbino in the choir, and the first works by Peterzano in Milan with the Vocation of the saints Paul and Barnabas and the Saints Paul and Barbabas in Listri where it still emerges called the influence of his Venetian training, in particular Titian and Tintoretto; Finally, it should be noted that some works by the Campi and Lomazzo brothers once present in the church are now on display in the Pinacoteca di Brera.
The prototype of the church of the Counter-Reformation: the church of San Fedele
In the program of the counter-reform of Cardinal Carlo Borromeo in the city of Milan, there was also the intention of bringing into the city the company of the Jesuits whom he had known in his Roman stays: the cardinal placed their headquarters in the old church of San Fedele, proved inadequate to Borromian propaganda, for which Pellegrino Tibaldi was commissioned to build a new building. The construction lasted for many years, and among the various interventions there was also the demolition of some blocks to make room for the square in front: on the structure of the church have been made many comparisons with the Basilica of Santa Maria degli Angeli and the Martyrs and the RomanChurch of the Gesù del Vignola, together with which it is considered the model of the “church of the Counter-Reformation”.
Although the two architects had never come in contact, the superintendent of the Jesuit buildings Giovanni Tristano was able to assist the Tibaldi in the Milanese shipyard: both churches have a single-nave layout with the natural vanishing point towards the altar dominated by the space brighter than the dome, thus creating vertical directionality and anticipating the themes of the “static dynamism” baroque. The analogies continue in the decoration of the façade on which the decoration is concentrated to the detriment of the sides.
The façade of the building was designed taking into account the subsequent opening of a square, which would however have been restricted, so that the church’s dimensions and proportions were sized to give the small space an aspect that is as monumental as possible. The compositional scheme of the front is set on two horizontal orders and divided into five vertical scores: in the central there is the portal with curvilinear tympanum supported by columns of the Corinthian order; the lateral partitions show a certain symmetry with bas-reliefs and niches, all surmounted by a triangular tympanum. The façade thus obtained represents a meeting point between the typically Mannerist plasticism and the canons of the counter-reformed architecture.
The same division in two orders of the front is also taken from the lateral façade, whose superior order rests directly on the lower order, rather than being set back as usual to create the space for the side chapels: this solution was unprecedented in 16th century architecture both Milanese and Roman and as such was also one of the first churches to present the two orders of the main facade of equal size. If there are examples of façades with overlapping orders of equal width, the façade still covered the sides. For the scheme of the main facade as well as for the decorated tympanum, finished according to the original design only in the nineteenth century, Tibaldi took inspiration from the score in five vertical fields of the project of thechurch of Santa Maria near San Celso. As for the portal, Pellegrino Tibaldi adhered to the model of the Church of Jesus despite numerous stylistic debts to Michelangelo in the side window windows, whose cornices follow those of the Palazzo dei Conservatori, or in the niches similar to those of the Basilica of San Pietro.
The churches of the Instructiones
The church of Santa Maria near San Celso was begun in the fifteenth century, but much of its appearance is due to projects realized since 1570. The façade was designed by Alessi, originally based on Michelangelo’s drawings for the Florentine Basilica of San Lorenzo. The project was later modified and completed by Martino Bassi: you still recognize the typical elements architect from Perugia already in Palazzo Marino, which translate into a rich decoration plastic, in contrast, however, with the quadrangle of the late Renaissance Solari existing. The façade is in marble, divided into four horizontal and five vertical orders, and is centered on the rich portal with a broken tympanum supported by four columns: the central part is the most decorated, with statues surmounting the portal, rich bas-reliefs, and the large window contained in the space of a double order of pilasters holding the tympanum with carved stories of the Bible. The rich decoration of the front is extended over the entire space available from statues and bas-reliefs made mainly by Annibale Fontana and Stoldo Lorenzi, whose main theme is the Annunciation and the Assumption of the Virgin Mary.
The church has inside a sculptural apparatus as rich as outside: in particular, there is the statue of the Virgin (1586) in the altar of the Virgin of Miracles designed by Martino Bassi and San Giovanni Evangelista in the tribune by Fontana, and the David and Moses alongside the counter-organ, and San Giovanni Battista with Abraham (1578) in the tribune of Stoldo Lorenzi. The chorus is in fact a work of sculpture due to the complexity of its forms and was realized by Paolo Bazza from 1570 to be finished many years later with many modifications to the original project. The high altar, designed by Martino Bassi in 1584, is in line with the rich decorations of the church and well represents the Milanese decorative arts which at the time reached their maximum splendor: the wooden choir was designed by Galeazzo Alessi. Finally it is worth mentioning the altarpiece of the Resurrection by Antonio Campi, in which the painter shows off his skill in illusionistic painting.
Among the various renovations of ancient churches, there was that of the Certosa di Garegnano, with the addition of the portico and the design of a new facade starting from 1573 under the direction of Vincenzo Seregni: the current facade divided into three orders Decreasing does not follow perfectly the original project, so it is thought that he underwent some changes during the early seventeenth century given his references to the first baroque style. Although the interior decoration is mostly seventeenth-century, there are frescoes of the Crucifixion, the Adoration of the Magi and the Shepherds and the altarpiece depicting the Madonna with Child and Saintsby Simone Peterzano, in which he shows a pictorial mitigated of the counter-reformist norms imposed by the Carthusian friars of the church.
Among the most important works of Martino Bassi we can also include the reconstruction in classical forms of the dome of the Basilica of San Lorenzo, collapsed in 1573: the new forms of the dome probably inspired the Borromini for the dome of Sant’Ivo Wisdom. The reconstruction had to actually involve the structure in its entirety, but thanks to the strict control of the archbishop the works included only the dome and the reorganization of other minor parts of the church, leaving intact, by express order of Borromeo, the plant with the path ring.
The project for the conclusion of the Santa Maria della Passione yard dates back to 1576, when Martino Bassi transformed the building with a Greek cross plan, a structure that was invisible to the post-government authorities, in favor of a Latin cross structure extending the nave. final result of a church with three naves, with the two exterior flanked by semi-circular semicircular chapels: the bishop of Famagusta Gerolamo Ragazzoni in a visit to finished works praised the work for adherence to the new architectural standards. The choice of chapels visible on the outside as semi-cylinders was one of the most particular solutions of the work and traces the incomplete project of Brunelleschi for the Basilica of Santo Spirito in Florence. Among the works relating to the second half of the sixteenth century inside the church we can find the organ doors by Carlo Urbino, the right transept frescoed by the painter cremasco and the altarpiece of the Crucifixion (1560) by Giulio Campi. The imposing dimensions that resulted from the modification of the church led to the reconstruction of the street that led to the front of the church: from a tortuous and narrow alley we passed to a wider and rectilinear road that made better observe the church.
On the contrary, there are two churches built on a central plan despite the favor of the Latin cross plan Borromeo, both of Tibaldi: the church of San Carlo al Lazzaretto and the church of San Sebastiano, which are also united by the common construction circumstance, or in function of the plague that in those years gripped the city.
The church of San Carlo al Lazzaretto was commissioned by Carlo Borromeo in 1580 to Pellegrino Tibaldi, although in fact the works were followed by Giuseppe Meda. The structure was composed of a central octagonal plant with as many openings; the building originally served as an open temple for the altar already present in the center of the Lazzaretto. The choice of the central plan obeyed the precise functional criteria indicated in the Instructiones, in fact, the central open plan would have allowed all those present in the hospital to attend mass without having to move, a criterion not unimportant if you think about the plague conditions: the solution was taken years later for the construction of the Lazzaretto di Verona chapel.
The work of the cathedral
Finally, a speech by Cardinal Borromeo could not be omitted to adapt the city’s cathedral to the new Tridentine norms, thus giving a blow to the works of the factory that proceeded slowly from the fall of the duchy.
The main interventions for artistic value and number were the work of Pellegrino Tibaldi, “favorite” of the cardinal: one of the main debates at the time was for the façade project. The Tibaldi proposed a solution in line with the style of the era that separated from the rest of the Gothic cathedral that can be included among the most important unrealized projects of the time.
The project included a façade on two orders: the lower one marked by giant Corinthian columns supporting the trabeation, corresponding to the side aisles, and a higher order corresponding to the central nave flanked by monumental obelisks. Only the five lower portals and the windows above the four side portals were actually made of the project, but not under the supervision of Tibaldi, but of his major pupil Francesco Maria Richini.
Inside, due to Tibaldi are the three monumental altars of the right aisle near the transept, which share the structure in polychrome marble with the pediment supported by columns of Corinthian order, adorned with various statues. His major contribution to interior decoration however took place in the presbytery area: his are the designs of the temple with a square plan with Corinthian columns above the baptistery, and most of the arrangement of the high altar, on all the ciboriumin bronze in the form of a circular temple with eight columns supporting a dome adorned with statues, a masterpiece of the sixteenth-century fuseria art. Under the altar is the crypt of St. Charles Borromeo, organized on two annular paths, circular and octagonal respectively, on which however a furious controversy broke out with Vincenzo Seregni on alleged structural problems of the structure. Finally, at the Pellegrini there is the marble flooring of the cathedral and the drawings for the wooden choir carved with the Stories of Sant’Ambrogio and History of the Milanese archbishops. Of this period are finally the north and south organ, commissioned respectively to Giovanni Giacomo Antegnaniand to Cristoforo Valvassori, and the relative wings of Giuseppe Meda and Ambrogio Figino.
Opera di Leone Leoni is the funerary monument to Gian Giacomo Medici in the southern cross, commissioned by his brother brother Pope Pius IV to the Arezzo sculptor on a proposal by Michelangelo, originally asked for the work. The work is supported by six marble columns sent directly from Rome by the pontiff, in the midst of which the deceased is depicted as a Roman soldier, flanked by statues of the Militia and Peace, with two minor statues above the outer columns depicting the Prudence and Fame. Originally the sarcophagus was also present incast bronze, then removed by Cardinal Borromeo together with the various coffers of dukes and civilians in an attempt to contrast the phenomenon of secularization of the cathedral. However, the most famous sculptural work of the church is the skinned San Bartolomeo by Marco d’Agrate, famous both for the virtuosity of the representation of the skinned saint holding his skin, and for the ambitious and clearly visible signature on the work.
The building site of Palazzo Marino introduced Galeazzo Alessi to Milan: it is certainly the most famous urban work of the architect and the palace is considered as the most representative Milanese Mannerist civil architecture; after this work the Aixi commissions were steadily increasing until the Tibaldi arrived. After this first commission, however, the Perugian architect lacked the necessary research and evolution of his style, which led him to works, albeit dignified, far from the results of Palazzo Marino and the Basilica of Carignano, considering his best works. The palace was contracted by Tommaso Marino, Genoese businessman enriched in Milan under the Spanish government, who wanted to show the new power acquired. The work, in addition to the building, provided for the opening of a street that connected the building with Piazza Duomo in the immediate vicinity of Piazza Mercanti. The original project with the opening of the new street finds famous precedents with Villa Farnese di Caprarola and above all with Strada Nuova di Genova, with which it would have shared the width of the new district and the celebrative intent of the new ruling class.
A first project involved the ground floor in ashlar with columns Tuscan order, while the upper floor of the pilasters would resumed Tuscanic forms of the lower columns, surrounded by stone decorations Strain Adda, Saltrio stone and Carrara marble.
The building was completed many years later, with a completely new urban structure that upset the vision of the original project: Piazza della Scala in the sixteenth century did not yet exist, so the main front was located on Piazza San Fedele; while the current main entrance in Piazza della Scala was only carried out in the nineteenth century as a perfect copy of the other façade.
The final project conceived a building set on three superimposed orders of the two main fronts: on the ground floor it is marked by Doric pilasters that contain windows with ashlared shoulders and architrave with serraglie, with small windows on the cornice; the entrance portal is enclosed by twin columns supporting the balcony. The upper floor has fluted Ionic pilasters that contain windows with balustrade parapets and a broken curvilinear tympanum, also in this case surmounted by small windows. The second floor has windows with triangular tympanums surmounted by a frieze and heads of a woman holding the balustrade cornice. Inside, worthy of mention is the courtyard of honor, famous for its rich decorations, set up as a double loggia supported by twin Ionic columns: this composition is detached from the typical projects of the Alessi, which must have drawn from the local tradition: tradition observed and resumed first by Richini in the courtyard of the Brera palace and later by Borromini in the Trinitarian cloister near the church of San Carlo alle Quattro Fontane.
The Alessi with this project clearly breaks with the Lombard building tradition: the built entirely of stone building is detached from the Lombard conventional construction techniques, he wanted in brick structure cooked as covered with plaster, while the roof, no longer with the roof on the ground, it was made up of terraces of Genoese tradition.
Of the interiors, once famous for their splendor, remains very little because of the allied bombings that heavily hit the building. Notable among them is the Sala dell’Alessi, decorated with stuccos, pilasters and medallions, and the frescoes by the brothers Andrea and Ottavio Semino of Psyche and Love in the presence of the gods and the twelve allegorical figures on the walls, rebuilt after the war.
Other civil architectures
Another famous building of the second five hundred Milanese is the restructuring of Villa Simonetta: it was purchased in 1547 by the governor of Milan, Ferrante Gonzaga, who entrusted the restorations to various personalities including Domenico Giunti, to whom we owe the most scenographic addition, or the double loggia of Palladian inspiration that anticipates the forms of Palazzo Chiericati. The classicism of the loggia will also serve as a reference for the forms of the courtyard of the Senate palace by Fabio Mangone. The addition of the two side wings of the palace to form a courtyard that overlooks the villa’s private garden must then be added to the sixteenth-century project; inside there are fragments of frescoes by Flemish artists who worked on the construction site. The characterizing element of the façade is, as already mentioned, the classical arcade dominated by the double loggia: the portico consists of nine nine pillars with pilasters of tuscanic order, an order taken up by the columns of the upper floor of the loggia which resume the progress of the lower pilasters, while on the top floor the columns are decorated with Corinthian capitals. In the project there were references to famous examples of suburban villas of the time: in the entrance to the garden there were two fishponds on the model of Palazzo Te di Giulio Romano, while on the first floor there were trompe l’oeil columns set as projections those of the loggia with fake windows and frescoes that have now disappeared altogether, whose overall layout was inspired by the Loggia of the heroes of Perin del Vaga in the Genoese villa of the Prince.
In 1560 Pope Pius IV commissioned for his hometown the palace of the Giureconsulti in the space of Piazza dei Mercanti to Vincenzo Seregni; for the project, the architect did not hide the analogies with the new forms of the Palazzo Marino dell’Alessi, although the fifteenth-century reference with the open portico facade was added.
Due to Leone Leoni, a sculptor who was an improvised architect, is the house of the Omenoni, built by the artist to assert his prestige starting from 1565, with the parade of the eight telamons he did not fail to attract the attention of many, including that of Vasari, which he wrote in his Lives:
«Of beautiful architecture that is not perhaps another similar in all Milan»
The building is emblematic of the period and of the Milanese political situation: despite the strict provisions of Borromeo and the numerous attempts to control the public morals by the Church, on the entrance door a frieze depicting a faire emasculated by a lion showed off, clear intimidating signal to the ill-intentioned or enemies of the sculptor. The façade is also a good example of classicism with the addition of Mannerist elements. The first order of the façade is then marked by eight caryatids, to which correspond in the upper order eight columns of the Ionic order, which once ended on the cornice. The house, however, housed until the early seventeenth century a small private museum of Leoni, which contained among the various paintings by Titian, Correggio and Leonardo, a plaster cast of the equestrian statue of Marcus Aurelius and the Atlantic Code by Leonardo Da Vinci.
Among the most important interventions wanted directly by Carlo Borromeo we find the Archbishop’s Palace, commissioned by Tibaldi starting from 1569. Despite the neoclassical reconstructions by Piermarini, one can still observe the courtyard enclosed by a double-arched open gallery of round arches with ashlar pillars and the Mannerist portal.
Another civic palace of the time is Palazzo Erba Odescalchi, attributed to Tibaldi and its collaborators and built around 1570: the only element in Milan is the ellipsoidal dome that traces the progress of the entrance hall and the stairs, also elliptical, which they create a singular illusion of height, in fact, although the stairs serve only one floor to the user, the space seems dilated thanks to the perspectival crushing of the ellipsis; this solution will be reused in the years to come up to Baroque architecture. Another anticipation of the baroque theme is given by the elaborate portal with a broken tympanum supported by columns of the Corinthian order with double-curved shelves,.
The only major public work conceived by the Spaniards was the remaking of the Palazzo Reale, entrusted to Tibaldi, begun in 1574, works that were almost completely erased by the nineteenth-century neo-classical reconstructions. The works were very complex and concerned most of the building: the Tibaldi was also distinguished as a stucco artist and painter, and his work earned him the task of the most central and prestigious court in Madrid.
Late nineteenth century is also Aliverti palace, largely remodeled over the centuries: from the original period remain the porticoed courtyard with Ionic and Doric columns, with coffered ceilings and interior frescoes attributed to the brothers Campi.
Despite a florid economy and a certain artistic liveliness, Lombardy was considered a strategic military outpost, and as such most of the funds allocated to the city were spent for the erection of a second wall. The walls were begun in 1548 on a project by the engineer Giovanni Maria Olgiati: at its conclusion ten years later the walls wound in a pentagonal path for eleven kilometers, which made it the largest wall of European walls of the time. The city wall was organized into ten curtainsthat assumed approximately the shape of a heart, from which derives the Milanese anecdote that the new boundary wall was a romantic wedding present to Queen Margherita of Austria, with reinforced walls at the corners of Porta Comasina and Vercellina gate.
The building of the outer walls converging towards the castle brought a series of consequences for the city’s urban planning: the custom of the time was to grant free land outside the city to religious orders to build its headquarters; with the incorporation of a large slice of land within the city these privileges decayed and the State was able to reappropriate vast land and end the validity of favors. Secondly, the construction of the fortified ramparts, the spaces next to the perimeter wall, should have been uncluttered to allow the cannons to be fired and provide the necessary visibility; which prevented the building near the new walls. In addition to the reorganization of the lands incorporated with the new city walls, a large reorganization of the channels passing through the land that was once outside the city was necessary: this is to supply the water for the moat of the new walls, and for not upset the numerous channels and waterways necessary for the Milanese economy.
After the construction of the walls, in 1560 it was decided to reinforce the Sforzesco castle by building a sort of citadel on the ancient Renaissance court. The project was entrusted to Giacomo Paleari and included a project divided into three walls, which would take the form of a six-pointed star. The castle project was completed not without some changes only in 1612 under the supervision of Gabrio Busca.
Together with the walls, a monumental entrance to the city was built to celebrate the passage to Milan of Margaret of Austria, the future bride of Philip III, who was erected near the Bastions of Porta Romana. The Roman gate arch, sometimes erroneously attributed to Martino Bassi, was designed by Aurelio Trezzi: the appearance is taken from the Roman arches of the second and third centuries, with a main opening and two on the smaller sides, and from the Venetian military architecture of the Sanmicheli. On the front towards the countryside the main opening is bounded by two flat drafts ending on the trabeation with carved metopes; on the sides there are two bas-reliefs with shells with pearls, allusion to the name Margherita from the Latin margarita which indicated the pearl. The door remained for the entire next century a model for the construction of ephemeral apparatuses in the duchy.
Source from Wikipedia