Santa Maria Novella was the first great basilica in Firenze. The church was designed by Fra Sisto Fiorentino and Fra Ristoro da Campi and the construction began in the mid-XIIIth century. In the XVth century, the rich textile merchant Giovanni di Paolo Rucellai (1403–1481) hired the great Leon Battista Alberti (February 14, 1404 – April 20, 1472) to design the upper part of the facade of the church (1456–1470). Alberti designed a long frieze decorated with squares in the middle of the black and white marble facade.
In the XVIth century, the mathematician and cosmographer Egnazio Danti (April 1536 – October 19, 1586) lived in the convent of Santa Maria and he was commisioned to design and construct three astronomical instruments to do observations of the Sun. He designed a quadrant (on the right of the facade) bearing six sundials in 1572 and an equinoctial armilla (on the left) in 1574.
The third instrument was a gnomonic hole which he didn’t complete.
Additional information: you can find a statue of Leon Battista Alberti in the Courtyard of the Ufizzi Gallery:
Location: Santa Maria Novella (map)