Torre del Homenaje del Castillo dominates the townscape of Sos del Rey Católico from its position atop Peña Felizana, the highest rocky promontory in this historic Zaragozan municipality within Aragón's Cinco Villas region. The castle's origins date to the 10th century when Arab builders constructed the initial fortification on this defensible outcrop, which was later reformed by Ramiro II around the 12th century when wood construction was replaced with durable stone. The surviving Torre del Homenaje features a remarkably compact interior footprint of approximately twelve square meters, suggesting its original function as a watchtower rather than residential quarters, and remains the most significant preserved vestige of the 12th-century fortress. Strategically crucial as a border stronghold during the Middle Ages—first against Islamic expansion and later between Aragón and Navarre kingdoms—the castle exemplifies medieval military architecture and continues to mark Sos del Rey Católico's position as a historically significant Aragonese settlement.
