Different authors ascribe to the territory of Cabras five coastal towers, three of which are directly situated on the coast. They had the task to watch over the coasts in order to prevent the frequent incursions by the so-called "barbareschi", as well as to prevent the landing of infected boats or boats suspected of smuggling. The surveillance was particularly important near the so-called "tonnare" and fish pools, like in Cabras, which was more than once subject to pirate attacks.