On entering the baptistery, the immensity of the building is even more convincing than from outside. Here, in fact, we obtain an immediate sense of the proportions. The is 55 mts and the diameter 35.50 mts: bare values, but from inside, at this moments, the height and and amplitude have another meaning, so penetrating as to cause admiration and dismay. We are, in fact, under the huge vault of the dome and in front of a grandiose annular nave discreetly lighted by the numerous windows distributed all around. Our attentions will be very soon drawn by the Font and the Pulpit. The Font is located in the middle of the temple on three steps. It's a work of GUIDO BIGARELLI.
In the middle of the basin there is a statue of the Baptist, of ITALO GRISELLI. The font is enriched with eight faces decorated by central rose-windows and by geometrical marble decorations. The Pulpit is a great work of the year 1260 of NICOLA PISANO. The artist for realizing the last panel of this opera, took advantage of the work of his still very young son Giovanni and of ARNOLFO DI CAMBIO, both of which later, cooperated with him in realizing the pulpit for the cathedral of Siena.