The façade and the dream

More precise information about the original design can be traced back to a design from the early 16th century, in which a certain Antonio Labacco drafted the floorplan and elevation of the building. It is unclear if this design really conveyed Alberti's original ideas. Nevertheless, the most salient aspect of the building is still immediately apparent today - the configuration in the form of a Greek cross. It also shows a vestibule open at the sides and, from an elevated perspective, the overall appearance of the church, which was never fully realised. The draft also displays a large cupola and double tympanum, overlooking a façade similar to the one at Sant'Andrea.

The legendary origins of the project are particularly interesting. Towards the end of 1459, the year of the Diet of Mantua, Ludovico Gonzaga had a dream. The Chronicle of Mantua by Andrea Schivenoglia tells us: "It is to be recalled that in the year 1460 work was started in the month of march on the church of San Sebastiano on the grassy area of Redevello. Ludovico ordered it after a dream that he had one night.."
Redevallo was a grassy area in the south of Mantua, not far from the city walls. The dedication to St. Sebastian can probably be attributed to the protection that the Saint offered when the plague was raging throughout the city.

The Church is now divided up on two floors, as was undoubtedly originally planned. It is a simple and elegant design, with a tympanum surmounting the square geometric form and five exterior openings. The three doors in the middle are adorned with copies of three low screens from the 15th century, which are now housed at the City Museum. The upper part features an architrave in two sections and a Syrian arch that stands above the tympanum.

In-depth studies have revealed the perfect mathematical proportions of the elements from the original design. But this claim is overshadowed by the church's turbulent history. In the 1470s, just after works had commenced, there was a dramatic turn of events when, according to the Marquis of Mantua, Fancelli decided not to follow Alberti's original instructions. It is worth noting too at this point that Alberti himself appeared to have lowered the height of the chapels while the building work was being carried out.

The interior of the vestibule is symmetrical to the openings on the façade.

In Spring 1461, after the foundation works had been completed, it was a close colleague of Alberti's, the engineer Giovanpietro Figino, who carried on with the works. It is unclear how many stairs should have reached the vestibule and where they were placed. It is clear that the lower part of the church was included in the original design. Fancelli was then no longer involved with the project, while Alberti provided fresh instructions. From 1470 onwards, progress on the church began to slow considerably. When Ludovico died in 1478, the impetus for the Prince's private church faded away altogether. In 1488, the church was transferred to the Lateran Canons. They then took charge of completing the cross. The bell tower was completed in 1569, although the church had already been consecrated in 1529. It is interesting to note that the loggia to the side of the church was also an original Renaissance design, albeit reworked in 1882.

The loggia on the left-hand side, which once probably gave access to the vestibule.

The exterior of the church on the right, with corresponding apse. Below, two windows of the crypt.

The Church of San Sebastiano, which was completely unique in its original design, was subject to vicissitudes that gradually sidelined it to the margins of city life, before it was rediscovered and used once again in the 20th century. A large part of this was undeniably the fact that it was affiliated with a monastery, which transformed it from being a symbol of dynastic power to a mere place of worship in the hands of a religious community.