Alberti's San Sebastiano, Mantua
San Sebastiano was commissioned by Ludovico Gonzaga, the ruler of Mantua at the time. For San Sebastiano, Alberti implemented a centralized Greek cross plan. Started in 1460 as one of the only buildings Alberti designed from the ground up, it was never quite finished the way he had intended it to be. The two halves of the temple facade are framed by pilasters, the central void divides the structure up through the pediment, again working off triumphal arches. The church was meant, as you can see by the diagram, to be elevated over a ground level crypt using one grand staircase. Instead the crypt was left open, and two side staircases were added. Six pilasters are shown in the plan, yet there are only four on the actual building. Centrality and symmetry were observed.