In wartime situations, it controlled the space between Lisbon and the South, between the Tagus and Sado rivers.
During the Islamic period and the Christian offensive in the 12th and 13th centuries, this geostrategic position was compatible with other fortified sites—Coina, Sesimbra, and the Sado riverbank. In the surrounding area—with good conditions for grazing and a large area of agricultural land—some rural communities settled during the Islamic period, such as the village of Alto da Queimada (Serra do Louro).
Inside the wall, the ruins of the Church of Santa Maria do Castelo welcome visitors: Palmela's first parish church, probably from the 12th century (founded by King Afonso Henriques?), subject to interventions mainly in the 16th and 17th centuries and severely damaged by the 1755 earthquake.
The walls, the pentagonal Keep—a 16th-century construction—are part of the original structure. The castle dates back to the 14th century, where the Bishop of Évora, D. Garcia de Meneses, was imprisoned in the waterless cistern for conspiring against King John II. The bishop died there from poisoning in 1484. The parade ground and barracks are worth visiting.
As it stands, the castle is the result of several construction campaigns—repairs, reconstructions, and expansions—up until the 18th century. Archaeological work has identified some sections of the wall from the Islamic period, and other construction phases are recognized, likely dating from the post-reconquest period and, later, from the reign of King John I. The bastion system that surrounds the first line of fortification was commissioned by King Pedro II.
In the house of the Prior-Major of the Order, or the military commander of the fortress—after the abolition of the orders (in 1834)—the explorer of African lands, Hermenegildo Carlos de Brito Capelo, son of the fortress's governor, was born on February 4, 1841.
Palmela Castle was classified as a National Monument by Decree-Law of June 16, 1910.
Parking outside the walls is recommended.