The city of Palma was founded on May 3, 1637 in the barony of Montechiaro, by the twin brothers Carlo, Barone Tomasi, and Giulio, who a few years later would succeed him in the title. The actual architect of the foundation, however, was a powerful uncle of the twins, Mario Tomasi de Caro, Captain of the Holy Office of the Inquisition of Licata, and governor of the same city, from which Carlo and Giulio Tomasi also came. He too, together with his cousin priest Carlo de Caro was present at the laying of the first stone of the Church of the Virgin of the Rosary.
The city project, designed according to an ideal orthogonal plan, and recalled by a report written by the astronomer and first archpriest of Palma Giovan Battista Odierna. In a canvas preserved in the sacristy of the Mother Church, the Today is depicted at her study table with a square plan drawing in the background, clearly visible, with the title “Chronologia Terrae Palmae”.
The town stands on a rocky hill from which it dominates the valley below which extends to the sea. The historical monuments of the second ducal palace (1659), the beautiful Mother Church, (1666), at the top of a large staircase and the Benedictine Monastery, (1637) stand out in the foreground, clearly visible from the fast flow that crosses the valley. ) first building in the city.