The origins of the temple
dedicated to St. John the Baptist, later patron
saint of the city, are still uncertain. According
to tradition, it was founded in Roman times
and dedicated to the god Mars. Several sarcophagi
have in fact been found in this area, today
in the Museum of the Opera del Duomo, as was
the famous statue of Mars, which mediaeval
chronacles tell us stood at the entrance to
Ponte Vecchio. However some scholars think
that the building was the Praetorium and the
statue that of a barbarian king.
Dante himself declared that
his "beautiful San Giovanni" (Inferno,
canto XIX) was a classical Roman building;
excavations carried out in this century have
in fact discovered remains of Roman constructions
underneath the Baptistery and the Cathedral,
built in the north-eastern area of the first
ring of walls.
The foundations of the first
Baptistery of San Giovanni, dated from 4th-5th
century circa, was certainly built on top
of these ancient buildings.
Its octagonal shape, the
two lower orders, the attic and the springer
of the cupola (in other words its basic architectural
structure), date from the early Christian
construction, which was possibly altered or
completed in the early decades of the 7th
century during the Longobard rule.
