Castello dei Conti d'Aquino, Medieval castle in Roccasecca, Italy.

Castello dei Conti d'Aquino is a stone fortress built on a mountain peak in Roccasecca, featuring defensive walls, a central courtyard, and a watchtower. The structure displays typical medieval military design with carefully planned defensive elements and original architectural details.

Built on Monte Asprano in 994 at the behest of Abbot Mansone of Montecassino, the castle guarded the lower Sacco-Liri valley and the Melfa confluence. Count Adenolfo III destroyed it in 996; it was rebuilt after the year 1000 and enlarged by Landolfo and Rinaldo II d'Aquino with a cylindrical tower that withstood Henry VI's siege in 1197. Frederick II stayed here in the 13th century, and tradition holds that Thomas Aquinas was born in 1225 in the rooms still called "casa di San Tommaso".

Local documents from the late 13th century call Roccasecca a "Universitas hominum", meaning it had its own administration even while ruled by the d'Aquino lords. The castle's inner rooms are still known as the "casa di San Tommaso", because some historians hold that the Dominican theologian Thomas Aquinas was born there in 1225.

The fortress is accessible through the western entrance, which leads to the main courtyard with views over the surrounding Lazio countryside. Wear comfortable shoes for the steep climb and uneven ground around the site.

A large rainwater collection cistern is integrated into the fortress grounds and shows how medieval strongholds managed water supply in mountain locations. This practical system was vital for residents during extended sieges.