This is a very old place, where human presence has been recorded since the Paleolithic. Archaeological remains show a Lusitanian fort and Roman occupation in the so-called field of S. Lourenço, at the foot of the hill. Traces of Visigoth and Arabic remains have also been found.
D. Afonso Henriques conquered Monsanto from the Moors and in 1165 he donated it to the Order of the Knights Templar, who ordered the construction of the Castle. It is due to D. Sancho I the repopulation and rebuilding of the fortress, dismantled in the fights against Leon, and repaired again a century later by the Templars. 
In the 19th century, the imposing medieval Castle of Monsanto was partially destroyed by the accidental explosion of the ammunition magazine.
We invite you to visit the remains of the mighty castle on the steep hillside where you can see the alcazar, the ramparts, and watchtowers, as well as the beautiful ruins of the 12th-century Chapel of S. Miguel and the Chapel of Santa Maria do Castelo.