The interior is in the form of a basilica, the double aisles being borne by ancient columns, and contains ambones and a candelabrum of 1311, the former resting on columns supported by lions, and decorated with reliefs and coloured marble mosaic. The castle at the highest point of the town was erected in the 14th century.
The inconvenience of having a single ambo led to the substitution of two separate ambones, between which these various functions were divided, one on the south side of the chancel being for the reading of the gospel, and one on the north for reading the epistle.
Ambones were made of wood or else of costly marbles, and were decorated with mosaics, reliefs, gilding, &c.; sometimes also covered with canopies supported on columns.
The churches in Rome possess many fine examples of ambones in marble, of which the oldest is probably that in S.