Sant’Andrea in Mantua: Etruscan Temple or Cruciform Church?

by Eugene Johnson, appearing in Volume 41

The first part of this essay, published in Issue 39, introduced Alberti as the architect who made the pagan architecture of Greece and Rome “safe” for Christian churches. He revived accurately entire building types of the architecture of antiquity, particularly the temple front of the Greeks and the triumphal arch and vaulted basilica of the Romans. Alberti gave these pagan forms Christian purpose. For example, for the Romans the triumphal arch signified a military victory, but for Christians it signifies victory over sin and death.

The façade of Sant’Andrea in Mantua, begun in 1472, fuses the Greek temple front and the Roman triumphal arch. Photo:

Leon Battista Alberti’s last, greatest, most influential church design was for Sant’Andrea in the northern Italian city of Mantua. In it, he fused the temple front, the triumphal arch, the secular basilica, and the mausolea of the ancients into a new type of Christian church that served not only his purposes, but also those of future centuries. At Sant’Andrea he replaced the traditional aisled basilicas of Christianity with the single nave church flanked by side chapels, a type that played a major role in church architecture for the coming centuries.

Alberti’s Letter

The attribution to Alberti is guaranteed by an autographed letter he wrote to his friend and patron, Lodovico Gonzaga, Marquess of Mantua, on 20/21 October 1470. The letter gives us not only a vivid sense of Alberti’s astute handling of a client, but also his only preserved, first-hand account of his understanding of the requirements of a design.

“I understood in these days that your highness and these your citizens were thinking of building here at Sant’Andrea. And that your principal intention was to have a large space where many people would be able to see the blood of Christ,” he wrote.

“I saw that model of Manetti’s. I like it. But it does not seem to me apt to your intentions. Consider and imagine this that I send you. This will be more capacious, more enduring, more worthy and more felicitous. It will cost much less. This type of temple was known among our predecessors as the Etruscan. Should you like it, I will see to drawing it up in proportion.” He signed the letter “Your servant Baptista de Albertis.”

Alberti begins with a short, clear statement of the function: a large space where a crowd of pilgrims would be able to see the blood of Christ. Sant’Andrea conserves one of the principal relics of the Christian religion, blood that the crucified Christ shed when his side was pierced by the spear of the Roman soldier Longinus. Converted on the spot, Longinus is said to have gathered up the blood-soaked earth of Calvary and carried it with him until he was martyred in Mantua, a city of Etruscan origin near the birthplace of Virgil.

Around AD 800, Saint Andrew is believed to have appeared in a dream to reveal to a local where the blood had been buried during the intervening centuries for safekeeping. A church, about which we know nothing, was built to house the relic. During dangerous, post-Carolingian times, the blood was buried once again. Around the year 1000, Andrew appeared in a second dream to reveal again the location of the blood. A new church, about which we know slightly more, was built on the site where Sant’Andrea stands today.

In 1401, Gianfrancesco Gonzaga, first Marquess of Mantua, instituted an annual custom of displaying the blood, contained in two vases, on Ascension Day. Pilgrims began to arrive in Mantua in large numbers to view the precious relic. By the time of the Council of Mantua of 1459, when Pius II gathered together representatives of the European powers to organize a crusade against the Ottoman Turks, the Romanesque church had begun to show its age and functional inadequacy.

Gianfrancesco’s son Lodovico decided to build a new church to do honor to his city and the relic and to accommodate the pilgrims. Alberti saw his chance and seized it.

Seizing His Chance

First he had to dispose of the model already made by Manetti, a Florentine architect of modest talents, without offending Lodovico, who presumably had commissioned it. He wrote that he “liked it, but...” The “but” leads into his statement that Manetti’s model doesn’t appear “apt” to Lodovico’s intentions.

Aptness to purpose is a crucial criterion for Alberti. In his treatise on architecture, De re aedificatoria, he accepts Vitruvius’s criteria for good architecture: utilitas, firmitas, venustas (function, structure, and visual delight). To this triad he adds a fourth qualification, “ad usum apta,” appropriateness for its intended purpose. Alberti’s building is just that. The rest of the letter cleverly gives all the ways his building will be superior to the Manetti design, including a point of great importance to a ruler always short of cash: it would cost much less.

Alberti’s final rhetorical device (splendidly analyzed by the Italian scholar Massimo Bulgarelli) that skewered the Manetti project with a learned thrust is his statement that the design is based on an ancient temple form known as the Templum Etruscum. Not Roman, but the more ancient, and specifically Mantuan, Etruscan. Mantua was said by Virgil, among many other ancient writers, to be of Etruscan foundation.

As Angelo Mazzocco has pointed out, the Florentine humanist Leonardo Bruni composed a letter in 1418 for Gianfrancesco Gonzaga, De origine Mantuae. The purpose of the letter was to demonstrate the inaccuracy of a remark by Dante that Mantua was a Roman city, and that Virgil, who noted its Etruscan origin, was the authority to trust. Alberti of course was acquainted with his fellow Florentine scholar, Bruni, who had died in 1444. Lodovico Gonzaga surely knew the Bruni letter, solicited by his father. From Lodovico, Alberti could have learned of it.

What could have been more “apt” than to recall the Bruni letter in Alberti’s missive to Lodovico? And it is important to remember that Alberti always based his designs on local monuments: the Arch of Augustus in Rimini, San Miniato al Monte in Florence. Mantua had no remains of Etruscan buildings; Alberti only had literary accounts to go on.

Plan of Sant’Andrea drawn by Ernst Ritscher, 1899. Image: S. Andrea in Mantua: The Building History by Eugene Johnson

Alberti’s Model

The final line makes clear that Alberti sent Lodovico a sketch with the letter, since he had not yet rendered it in proportions, an undertaking that Alberti elsewhere tells us often surprises him when he realizes that his first thoughts had to be corrected by rendering them in proper mathematical ratios. We know that he had had a wooden model built for the Tempio Malatestiano. Once Lodovico chose Alberti’s design—we learn from a letter from Lodovico to Alberti that he planned to discuss the Albertian scheme with its designer before going ahead—Alberti must have ordered a model made for Sant’Andrea. He would have known that he would rarely be on site to supervise the construction, as was always the case with his buildings. But he would hardly have been able to predict that he would die in the spring of 1472, just before the actual construction began.

The Florentine stonemason Luca Fancelli, to whom Alberti explained the design, supervised the first phase of building, which saw the west porch and nave completed by the 1490s. In the sixteenth and seventeenth centuries the transepts, crossing, and choir of the present Latin Cross plan were added. Final completion came only in the eighteenth century with the dome designed by Filippo Juvarra.

At Sant’Andrea, Alberti had only a single old structure to take into account, the bell tower now adjacent to the façade that had been recently constructed under Gianfrancesco Gonzaga. He was free to bring his full creative powers to bear on a church that would come to set a standard for hundreds of Christian churches in the future. The challenge was to find a fitting form for a large church that would house the blood that Christ shed to ensure the triumph of the faithful over sin and death.

The site, once cleared of the eleventh-century predecessor, was hemmed in on the north side by a Benedictine monastery and on the south by shops and houses that faced toward a market square and the town hall. To the west opened a small piazza on which the church would face and through which pilgrims would approach.

A Fusion of Forms

Alberti greeted those pilgrims with a fusion of pagan architectural forms, the Greek temple front and the Roman triumphal arch. No ancient architect would have committed the architectural faux pas of fusing two forms developed for two unrelated purposes.

The front plane of Alberti’s façade acts like a work of low relief sculpture—a technique at which his Florentine contemporaries excelled, particularly Donatelllo in his rilievo schiacciato—to weave the horizontals and verticals of the two forms together. The unbroken verticals of the giant order of pilasters simultaneously hold up the pediment of the temple front and frame the central arch of the victory monument. The façade literally embodies the church victorious. Form and content are one.

The key detail in the success of this fusion of types lies in the way Alberti gouged the entablature of the smaller order of the façade back into the depth of the walls, so that it does not project forward, as it rightly should, to interrupt visually the verticals of the pilasters. On the façade once appeared two frescoes by Andrea Mantegna, the Gonzaga court painter, and assistants that underscored the meaning of the architectural forms. In the roundel in the pediment appeared Christ, risen from the dead, flanked by Andrew and Longinus. Above the main portal appeared the Ascension of Christ.

The barrel-vaulted interior of Sant’Andrea. Photo: Palazzani

Behind the plane of the façade, Alberti erected a spacious porch with a central barrel vault poised above lower, transverse barrels, all three decorated by inexpensive terra-cotta rosettes of three different forms. An elegantly carved stone portal, the only expensive detail, frames the central door to the interior.

The triumphal arch of the porch leads to the startling experience of spatial expansion that overwhelms first-time visitors entering Sant’Andrea—an experience surpassed, at least for me, only by the even more exhilarating effect of walking into the Hagia Sophia in Istanbul. Alberti managed this effect brilliantly.

The pilgrim enters a vast interior, sixty feet wide, ninety feet tall, and almost 300 feet long, dimly lit and overarched by a single great barrel vault. To either side the nave is flanked by three barrel-vaulted side chapels separated by piers faced with pairs of giant pilasters. The barrels of the side chapels are the same height as that of the central bay of the porch. The tallest central element of the exterior becomes one of a series of lower elements beneath the wide, billowing vault of the nave.

Alberti transforms the central element of the façade, a single triumphal arch flanked by paired pilasters, into a series of alternating piers and arches that march longitudinally toward the altar, as Ralph Lieberman’s photos demonstrate. Such unity between inside and out exists in no ancient building, at least to my knowledge.

Pagan Prototype

For the interior of this church designed to hold “molto popolo,” Alberti chose the Basilica of Maxentius/Constantine in Rome as an apt pagan prototype. That fourth-century building Alberti believed to have been an Etruscan temple, thus religious, even though pagan. Now we know that it was built by the emperors Maxentius and his conqueror, Constantine, as a hall to house law courts and other secular functions, as well as to honor the ruler who built it.

In Alberti’s time the basilica appeared in ruins, much as it does today: three remaining barrel-vaulted chambers that originally lined one side of the taller central space. Those chambers are the ancestors of Alberti’s side chapels. As usual, Alberti chose a pagan example that best suited his present Christian purpose.

By fusing the triumphal arch of the façade with the form of an ancient basilica, Alberti carried the theme of triumph into the space where crowds of the faithful would adore the relic of the blood. His uninterrupted barrel vault, replacing the sequence of groin vaults that once covered the central vessel of the Roman basilica, and the unbroken cornices from which it springs, focus the eye instantly toward the east end and the relic it housed.  Here Alberti puts to architectural use the recently invented one-point perspective to fix the pilgrim’s view on the space that contained the sacred blood.

The façade’s central arch and flanking pilasters (left) are reflected in the interior bay geometry (right). Photo: Ralph Lieberman

The Eastern End

How Alberti intended to terminate the interior to the east is not known from the early documents. Alberti’s sketch and model are long lost. Would it have consisted only in a single nave terminated perhaps by an apse? Or would there have been an element beyond the nave to house the sacred relics, the altar and the clergy?

Scholars have argued over this question for at least sixty years. At the Alberti Congress held in Munich in 1960, Richard Krautheimer explored at length the possible sources for Alberti’s description of an Etruscan temple in De re aedificatoria, including ancient mausolea and the Basilica of Maxentius/Constantine. In his treatise Alberti deliberately ignored the actual passage on Etruscan temples in Vitruvius that he knew perfectly well.

Krautheimer noted the resemblance of Alberti’s plan of the porch and nave of Sant’Andrea to Alberti’s verbal reconstruction of an Etruscan temple. Given the state of knowledge of the building history of the church at that time—the transepts, crossing, choir and apse were all thought to postdate 1597—he surmised that perhaps they were not part of Alberti’s original design, which would have consisted only of a porch and nave, terminated possibly by an apse.

By the time he republished this paper in his collected essays, he had learned that the transepts were built in the second quarter of the sixteenth century from my dissertation, which he supervised. For that reason, he said that the early remarks that the church had been continued according to the “modelo antico” of Alberti needed to be taken more seriously than they had been.

Krautheimer’s proposal of a single nave church was taken up enthusiastically in 1995 by Robert Tavernor in his monograph on Alberti’s architecture. In support of his argument Tavernor erroneously cited a letter from Lodovico to his son Francesco, the first Gonzaga cardinal, that states that two million bricks have been gathered for the structure, which will be finished in two or three years. In the letter, Lodovico actually says that he hopes to make such a good start in two or three years that people will be encouraged to donate to the building fund: “che in dui anni o tre se gli fara tal principio che sera casone di ingegliardire molto la brigata a spendergli....

The fifteenth-century chronicler of Mantua, Andrea Schivenoglia, who observed the first building campaign, wrote that construction was estimated to take a more reasonable twenty-two years, with completion in 1494. Tavernor claims that two million bricks were only sufficient to build the porch, nave and apse, thus guaranteeing that such a plan was the original one. Livio Volpi Ghirardini has pointed out that the building materials gathered included more stones than bricks (stones were cheaper), so that there was always enough material to construct a larger church.

Hypothetical reconstruction of Alberti’s design for Sant’Andrea by Livio Volpi Ghirardini. Image: Livio Volpi Ghirardini

The Answers

The evidence of the fabric of the church itself has finally yielded answers to this question. In my own book of 1975 on the church, S. Andrea in Mantua: The Building History, I proposed, on the basis of archaeological evidence I had discovered in the western crossing piers, that the present crossing and square transept arms were part of an original Latin Cross plan.

That proposal was superseded by evidence uncovered (literally) by Livio Volpi Ghirardini (hereafter LVG). Prefetto delle Fabbriche del Duomo e della Concattedrale di Sant’Andrea in Mantova from 1985 to 2014, he was the engineer charged with the care of the fabric of the church. LVG was able to strip plaster off the foundations of the western crossing piers to discover that their masonry is not bonded into the masonry of the extended walls of the present transepts.

Rather, the crossing piers were built to continue the exterior line of the nave walls across the end walls of shallow transepts whose depths would have been the same as those of the nave side chapels. In the southwest crossing pier, two walled-up windows once brought daylight into the staircases in the pier. Now they are covered over by the north wall of the western transept chapel.

Hypothetical reconstruction of the plan. Image: S. Andrea in Mantua: The Building History by Eugene Johnson, modified

A letter to Lodovico of February 1473 establishes that the foundations of the western crossing piers were laid during the first year of construction of the nave in 1472. These piers contain pairs of overlapping circular staircases entered through doors in the nave and crossing faces of each. The letter reported to Lodovico that, in the previous year a workman had committed “cento errori ... maxime circa le lumage” (100 errors…principally in the circular staircases), that is, in one of the circular staircases that lead to the crypt, located beneath the floor of the nave.

I published in 1975 my discovery of walled-up oculi, the same shape and size, and at the same level of those of the nave piers, now visible only inside the upper reaches of these staircases. Each pier contains two such round windows, one facing into the nave, the other into the transept.

LVG has also pointed out that the circular stairs are displaced to the outer corners of the crossing piers, so that most of the solid mass of each pier is available to support a dome over the square crossing of Alberti’s intended Greek Cross plan for the eastern end of the church.

To illustrate a possible appearance of the Albertian scheme, he has published a hypothetical reconstruction drawing of the Alberti model for Sant’Andrea, the details of which, as he makes clear, can only be tentative. The evidence provided by the western crossing piers conclusively demonstrates that when construction began on the church, under the direction of the Alberti-trained Luca Fancelli, a crossing was planned, following the model that Alberti had left behind. In fact, the second set of pilasters were added to the crossing piers in 1616 in imitation of the Gesù in Rome.

The Important Relic

LVG’s careful inspection of the evidence of the masonry of Sant’Andrea has put the Templum Etruscum hypothesis to a final rest. That hypothesis, proposed by modern scholars on the basis of two words used by Alberti for rhetorical purposes in a letter seeking the commission of a lifetime, cannot hold up against the evidence of the masonry of the church itself.

One problem with the Templum Etruscum hypothesis has always been its disregard for the importance of the relic of the blood of Christ, the centrality of which to the Christian faith deserves its own fitting architectural setting. Relics directly associated with the person of Christ himself have often received quite special architectural treatment: Guarino Guarini’s spectacular Chapel of the Holy Shroud in Turin being an example.

Plan of Ss. Annunziata in Florence. Image: Public Domain

In two earlier instances, Alberti himself had been involved with the design of centralized structures, one at the end of the nave of the Tempio Malatestiano in Rimini and the other in a similar position in the church of the Ss. Annunziata in Florence. We have no evidence for the function the domed rotunda in Rimini was intended to serve.

The case of the Annunziata is closely tied to that of Sant’Andrea. Gianfrancesco Gonzaga had left a donation to the church in his will of 1444. In 1449 his son Lodovico, captain of the Florentine armies, accepted responsibility for construction of the rotunda at the east end, to be dedicated to the Virgin Mary, the “Annunziata,” who was often honored in the Renaissance with dedications of centrally-planned buildings. As the mother of Christ, she obviously had a physical connection to him.

By the fall of 1470 Alberti had redesigned the earlier schemes of Michelozzo and Manetti for the Annunziata rotunda, just at the very time he sent Lodovico his letter with his design for Sant’Andrea. Given that history, it seems inconceivable, at least to this observer, that Alberti would not have wanted to give the Most Precious Blood of the Redeemer its own separate, noble housing. As the Italian scholar Arturo Calzona has pointed out, Alberti consistently displayed a fascination with church plans that combined a longitudinal nave with a centrally-planned eastern end.

What ancient source(s) Alberti may have based his design on we cannot know. Krautheimer, in his essay on the Templum Etruscum, makes clear that Alberti considered the numerous vaulted, centrally-planned Roman mausolea he knew in Rome and elsewhere in Italy as vaulted, centrally-planned religious structures. It seems reasonable to surmise that one or more of these may have served as a pagan basis of Alberti’s design for the climax of the interior of Sant’Andrea.

The relic of the Preziossimo Sangue di Cristo (Precious Blood of Christ). Photo: Lanfredi


One of the most brilliant and innovative aspects of Sant’Andrea is the way Alberti visually unified the theme of triumph with the themes of the Greco-Roman temple front and the Roman basilica to give the ensemble of the parts of the church a coherent meaning. The evidence of the façade and nave, with their knowing play of theme and variation, suggests that Alberti would have found a third way to fuse pagan forms to create an “apt” shelter for the Preziossimo Sangue di Cristo that would have completed a visually coherent sequence of effects that underscored the Christian meaning of the building and the relic it preserves and celebrates.