The oldest towers were built along the coast as early as Middle Ages. It is known that in Angevin period (1277), the commune of Agropoli owned the Tresino tower, which made it possible to see and, therefore, to signal to those of S. Francesco and Licosa.
It was, however, the viceroy Don Pedro de Toledo who planned a complete system of coastal towers to defend against raids, especially by the Berbers and Turks. His successor, Don Perafan De Ribera, put the plan into operation in 1563, with designs for the construction of seven towers "twelve spans square" (about 7.5 sm) between Agropoli and Salerno. The one at the mouth of the Sele, however, would be larger (20 spans square=approx. 21sm). In 1566, he gave order to for building to begin on the stretch of coast between Agropoli and Policastro.
At the same time, private citizens were prevented for building others, and those already built were requisitioned.
In 1608, the S. Francesco Tower in Agropoli had still not been completed and new taxes were imposed. It has been modified since, but like the others built after the order of 1566 (including Trentova which is now in ruins), it is square with sloping sides and embrasures. The ground floor was udes as a stable and for storage, the garrison lived on the first floor and the second floor was the look-out, signallinh and defensive firing position.
By 1594, the circular tower of S. Marco (which has also been privately modified) and others, such as the Paestum tower, were already complete. The defensive role of the towers of Agropoli included early warnings of danger. These were by means of fire or smoke signals to the neighbouring towers. They were used for this during the principal uprising, the Parthenopian (Neapolitan) Republic, the nineteenth century troubles and, finally, during the last world war.
In the old town, adjoining the Mainenti (now Rotoli) mansion which is built on the outer walls, there is the beautifl Renaissance square tower. This has a southern entrance and an upper floor with wide windows, above which there is a terrace with embrasures and battlements. There are similar towers at Ortodonico and S. Maria di Castellabate.

(souce: GuidAgropoli)