The Baptistery

The religious center of the city was already taking shape in this epoch. Fulcrum of the future Piazza del Duomo was the Baptistery of San Giovanni.
The construction of a Baptistery opposite Santa Reparata is believed to have probably been coeval to the construction of the church and part of a single project, though the first document in which San Giovanni is cited dates to the year 897.

Accepting this hypothesis, the dimensions of the new Christian ecclesial complex in the northeastern part of the city should have been similar to those of the old pagan complex dominated by the temple of Capitoline Jupiter, in the forum in the middle of the urban grid (corresponding to the northern part of today’s Piazza della Repubblica). This was very important, as it marked the cultural renewal that the Christian faith was carrying out (bringing about – effecting). There is a lack of reliable data as to the origin of Santa Reparata and the Baptistery. For this new religious pole, archaeological facts have led to various interpretations, though few scholars today accept the tradition whereby the Baptistery was built during the classical age as the temple to the god Mars.
It can be affirmed with certainty that the relationship between the Baptistery and Cathedral visible today, has existed since very remote times. Be it accepting the traditional dating that claims Santa Reparata was built in the early V century and the Baptistery even before, be it opting for a different chronological context, the thread that joins the Baptistery and its Cathedral seems to be truly ancient.
The present structure of the Baptistery conserves the octagonal aspect typical of Paleochristian baptisteries. This shape had a precise symbolic value that the Church fathers linked with Baptism: it evoked the idea of the octava dies, “the eighth day” that lies outside the cycle of the week, and therefore outside of time limited by earthly life: the day of the resurrected Christ and of eternity. This symbolism was readily interpretable until the XIV century, considering that the Baptistery of Florence was surrounded by a cemetery: one would cross through the land of death to reach the place where man “was reborn” to new life in Baptism.
The most important Christian complex of Florence had by then taken shape as a veritable holy area.