Santa Maria Novella is a Dominican church, being the Dominican one of the three main medieval Mendicant Orders, along with the Santa Croce church (Holy CRoss, Franciscan) and Santo Spirito (Holy Spirit, Augustinian).

In 1242 the now established and flourishing Dominican Florence community starts planning the extension of the small church.

Pope Innocent IV allow the Dominicans to grant indulgences in favour of whom have contributed with donations to the works.

The works start around 1246; the consecration is just in 1420 (Santa Maria del Fiore will be consecrated by Pope Martin V, who was actually living in Florence, not in Rome).
Between the Dark Ages and the Renaissance

Santa Maria Novella is a Romanesque-Gothic church to which it happened to be… in the cradle of Renaissance.

The Rucellai family, funding the work of the architect Leon Battista Alberti (1404 – 1472), gave Santa Maria del Fiore that Renaissance boost: the beautiful façade.