The Basilica of Sant'Andrea is a Roman Catholic co-cathedral and 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 1462 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 finished only 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 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