Castle of Alter do Chão

Castle of Alter do Chão is a medieval fortress positioned on elevated terrain in Portugal's Alentejo region, featuring stone walls with corbels arranged in an elliptical layout. The site contains remnants of defensive structures alongside the ruins of a religious building that once occupied the grounds.

The fortress was founded in 1357 under King Pedro I following the reconquest of the region from Muslim forces, with subsequent control passing to a military religious order. This transition shaped its role as a strategic defensive point for the surrounding lands during the late medieval period.

The castle represents a defining moment in local identity, serving as a symbol of medieval protection for the region's inhabitants. You can sense this connection when walking through the ruins, where religious and military purposes were closely intertwined in daily life.

The site is accessible from the nearby town square and offers clear views of the wall sections and foundations scattered across the area. A daytime visit works best to appreciate the full layout of the structures and the stonework details throughout the grounds.

A geodesic survey marker stands on the grounds, recording the scientific mapping of the region across centuries. This modern point creates an intriguing contrast with the ancient ruins, showing how different historical periods intersect at this location.