It was commissioned by
Pope Julius III, in completion of a vow relative to his escape following the
Sack of Rome, 1527. The small church on the
Via Flaminia, scarcely more than a chapel, was designed by
Giacomo Barozzi da Vignola in 1552 and completed the following year, while Vignola was also employed by Julius nearby at the
Villa Giulia. Sant'Andrea was the first church with an
elliptical dome and the first step toward the
Baroque world of elliptical forms. The interior space is vividly expressed on the exterior. The
tempio as it was long called, is an unadorned cube with a dentilled
cornice without a
frieze, surmounted by an elliptical low
dome masked by a high plain
drum with a comparable frieze, all in the gray
pietra serena more usual to
Tuscany than Rome. Applied to the street front is an extremely flat
pedimented temple front, whose unadorned frieze is continued alone round the sides of the building, dividing the cube in the proportions 2:3. Very flat
Corinthian pilasters, doubled at the corners, divide the applied facade in three bays, with shell-headed
niches flanking the door. The façade is divided into pilaster strips with a central portal open between two grated windows. ==Interior==