Castelo de Alter Pedroso

Portugal, Portugal

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Castelo de Alter Pedroso in Alter do Chão, Portugal, originated as a 13th-century fortified settlement conquered from Muslim control around 1216 under King Afonso II, who ordered its repopulation, and was donated to the Order of Avis by Afonso III in 1249.

Rebuilt in 1357 by King Pedro I—commemorated by a marble plaque over the main gate—and later held by Nuno Álvares Pereira before passing to the House of Braganza, it featured Gothic quadrangular walls with cylindrical corner towers defending the Alto Alentejo frontier.

Captured and razed by Spanish forces under John of Austria in 1662 during the Restoration War, its scant ruins—including a gate, wall fragments, and a small tower—were further diminished by 19th-20th century urban works like a cemetery and geodesic marker.