Castle of Campo Maior

Campo Maior, Portugal, Spain

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Castle of Campo Maior is a medieval fortress in Campo Maior, Portalegre district, Alentejo region, Portugal (not Spain), rebuilt by King Denis in 1310 atop earlier Moorish foundations after the town's reconquest and integration into Portuguese territory via the 1297 Treaty of Alcanices.

Strategically positioned on the Spain-Portugal border, it endured sieges during the 1383-1385 Crisis—falling to John I after six weeks—and saw major 17th-century bastion fortifications under John IV amid the Restoration War, transforming it into a key garrison with bulwarks by engineers like João Cosmander.

Further rebuilt after 18th-century Spanish assaults in the War of the Spanish Succession and Seven Years' War—including a 36-day 1712 defense—its ruins preserve a chapel and powder magazine amid whitewashed houses, now a historic monument drawing visitors to this flower-carpeted border town.