The Basilica of Sant'Andrea is a minor basilica in Mantua. It is one of the major works of 15th-century Renaissance architecture in Northern Italy. Commissioned by Ludovico III Gonzaga, the church was begun in 1472 according to designs by Leon Battista Alberti on a site occupied by a Benedictine monastery, of which the bell tower (1414) remains. The building, however, was only finished 328 years later. Though later changes and expansions altered Alberti's design, the church is still considered to be one of Alberti's most complete works. It looms over the Piazza Mantegna.
The façade, built abutting a pre-existing bell tower (1414), is based on the scheme of the ancient Arch of Trajan at Ancona. It is largely a brick structure with hardened stucco used for the surface. It is defined by a large central arch, flanked by Corinthian pilasters. There are smaller openings to the right and left of the arch. A novel aspect of the design was the integration of a lower order, comprising the fluted Corinthian columns, with a giant order, comprising the taller, unfluted pilasters. The whole is surmounted by a pediment and above that a vaulted structure, the purpose of which is not exactly known, but presumably to shade the window opening into the church behind it.
An important aspect of Alberti’s design was the correspondence between the façade and the interior elevations, both elaborations of the triumphal arch motif, the arcades, like the facade, having alternating high arches and much lower square topped openings.
The nave is roofed by a barrel vault, one of the first times such a form was used in such a monumental scale since antiquity, and probably modeled on the Basilica of Maxentius in Rome. Alberti possibly planned for the vault to be coffered, much like the shorter barrel vault of the entrance, but lack of funds led to the vault being constructed as a simple barrel vault with the coffers then being painted on. Originally, the building was planned without a transept, and possibly even without a dome. This phase of construction more or less ended in 1494.
In 1597, the lateral arms were added and the crypt finished. The massive dome (1732–1782) was designed by Filippo Juvarra, and the final decorations on the interior added under Paolo Pozzo and others in the late 18th and early 19th centuries.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.