The Romanesque bell towers have a massive structure, with thick, strong walls, similar to defensive towers. They are usually square and equipped with small windows: single-lancet windows, mullioned windows with two lights or slits. They can be present in the façade or in the transept. The towers served the function of announcing the religious functions, thanks to the presence of one or more bells, but they could also be equipped with mechanical clocks to mark the hours.
