Of the two towers, which are large, fortified and symmetrical, but of different height and shape, the one on the right serves as the bell tower, while the one on the left is unfinished in the first order. The right-hand tower, in particular, with four indented storeys and single lancet windows, had a fifth storey with a spire, which was unfortunately destroyed by lightning in 1807. The two towers reflect the classic Norman style, already seen in Cefalù.
