Castro Marim is a small town and a community (about 3,250 inhabitants) in the same-named county.
Coordinates: 37° 13′ N, 7° 27′ W
The small town is situated north of the N125 and is very well signposted.
Already in prehistoric times people have settled here. At the time of the Roman dominion the place was called Aesuri and was the terminal of the Roman road coming here from Beja (in today’s Alentejo). From 711 on, the fortification of the place was then converted to a defensive castle under Moorish rule. After changing conquests the Moors were definitely beaten and chased away in the year 1242.
The Order of Christ (successors of the forbidden Order of the Temple) had here its seat from 1319 to 1356. After their leaving, the place became insignificant for centuries. Only around 1640, in the course of the Peninsular War, it gained anew in importance. Another fortification has then been built, the Forte de São Sebastião.
The place is overtopped by castle and fortress. The alleys at the foot of the mountain upon which the castles lies are narrow and winding.