The Basilica della Santissima Annunziata was founded in 1250 by the seven original members of the Servite order. In 1252, a painting of the Annunciation, which had been begun by one of the monks but abandoned in despair because he did not feel he could create a beautiful enough image, was supposedly completed by an angel while he slept. Construction was completed in 1481, after Alberti's death. Its entrance is through a fifteenth-century arcade designed by the famous architect Michelozzo, which helps to outline the shape of the square in front, Piazza Santissima Annunziata, together with the portico of Ospedale Degl'Innocenti by Brunelleschi.
The facade of the church was added in 1601 by the architect Giovanni Battista Caccini, in imitation of Brunelleschi's facade of the Foundling Hospital, which defines the eastern side of the piazza. The Baroque decoration of the church interior was begun in 1644, when Pietro Giambelli frescoed the ceiling with an Assumption as a centerpiece based on designs by Baldassare Franceschini. The organ (1628) is the oldest in Florence and the second oldest in Italy.