Amasya Castle or Harşene Castle, is a fortress located in Amasya, northern Turkey. It was attacked, ruined, changed hand and restored many times in the history during the Persian, Roman, Pontic and Byzantine era. Amasya Castle was substantially restored after the conquest of Amasya by the Ottomans in 1075 AD, and remained in use until the 18th century when it lost its military importance.