At Alessano they pulled down the cathedral to make a bigger one, and when they had finished it they were no longer a diocese. The old Romanesque cathedral had been built between 1150 and 1200, and all through the first half of the eighteenth century it had been patched up again and again; in 1755 bishop Dionisio Latomo Massa decided to make it anew, and the plan of the local architect Felice De Palma called for pulling everything down except the bell tower. The works lasted more than eighty years: the church was reopened only in 1845. In the meantime, on 28 June 1818, the diocese of Alessano had been suppressed and joined to that of Ugento, and the new church was born already demoted to a collegiate. The front, neoclassical, has stayed unfinished. Inside, among the baroque altars, there is the Tobias and the Angel by Paolo Finoglio, one of the known names of the Caravaggesque school.
Before then Alessano had been the most important town of the Capo di Leuca: a bishop's see from Norman times, and under the Angevins the chief place of a county that took in Arigliano, Caprarica del Capo, Giuliano di Lecce, Miggiano, Montesardo, Patù, Presicce, Ruggiano, San Dana and Specchia. Its best season was that between the fifteenth and sixteenth centuries, when the town became a trading centre and drew families of rich Venetian merchants and a small Jewish community, which had its own synagogue in the street still called via della Giudecca; around the ducal court a literary movement flourished as well, and the Renaissance palaces of the centre are of that time. The name probably comes from the Greek Alexis with the suffix of belonging; tradition, instead, has it that the town was founded by the Byzantine emperor Alexius I Comnenus, but there is no document to confirm it.