The Baptistery is located at the heart of the old city. It was built between 1059 and 1128 to honor John the Baptist, patron saint of Florence. For a long time it was thought that the Baptistery had been built on the remains of a Roman temple dedicated to Mars, but now it is certain that it replaced an earlier Baptistery. Its Romanesque style with the solid columns and plain decoration is impressive. The octagonal design signifies the six days of creation, the Day of Rest and an eighth day of re-creation through the Sacrament of Baptism.