Tempio Leon Battista Alberti (San Sebastiano)

The Church of San Sebastiano in Mantua is an early Renaissance building designed by Leon Battista Alberti for Marquis Ludovico II Gonzaga. Begun in 1460 and never completed as originally conceived, it is known for its Greek-cross plan, mirrored crypt and later role as a memorial to the war dead.

Why it matters

Alberti’s San Sebastiano is one of Mantua’s two major architectural projects associated with the Renaissance theorist, alongside Sant’Andrea. Commissioned by Ludovico II Gonzaga, the church uses a Greek cross within a square, with three semicircular apses and barrel-vaulted arms; a similar plan appears in the crypt below. Its original purpose remains uncertain, though a Gonzaga burial church has been proposed. This ambiguity is part of the building’s architectural history.

What to notice

The central plan and four barrel-vaulted arms define the upper church; the crypt below repeats the arrangement with a separate entrance. A fifteenth-century staircase survives in the left-side loggia and offers evidence of Alberti’s architectural intentions. The present façade and frontal staircases reflect later alterations. A memorial chapel preserves the building’s twentieth-century role as a sacrario for the war dead.

Context and history

Construction began in 1460 under Ludovico II Gonzaga. Work proceeded slowly and later generations altered the design, leaving the building incomplete and its original purpose debated. Between 1922 and 1925, restoration adapted the church as a memorial to the fallen. That campaign altered parts of Alberti’s design, including the frontal staircases and vault supports, so the present building preserves both Renaissance ideas and later memorial interventions.