In the 17th century the edifice was restored with the addition of altars and the Sacrament Chapel by Matteo Nigetti (1614).
The façade features pilaster strips, blind arches and lozenges, and is decorated with 12th century intarsia.
The interior houses the panels of Madonna with Child (by Matteo Traini, 14th century) and of St. Nicholas Saving Pisa from the Plague (15th century), canvases by Giovanni Stefano Marucelli and Giovanni Biliverti, a Crucifix by Giovanni Pisano, a Madonna with Child by Nino Pisano and an Annunciation by Francesco di Valdambrino.
The lower part starts at the top of each side with blind arches including lozenges.
The bell has instead a good plan, with a single mullioned window on each side, and is surrounded by a gallery with small arches supported by columns.