The Church of Saint Simeon Stylites (Arabic: كنيسة مار سمعان العمودي‎ Kanīsat Mār Simʿān al-ʿAmūdī) is a historical building located about 30 km (19 mi) northwest of Aleppo, Syria. It is the oldest surviving Byzantine church, dating back to the 5th century. Built on the site of the pillar of St. Simeon Stylites, a famed hermit monk, the church is popularly known as either Qalaat Semaan (Arabic: قلعة سمعان‎ Qalʿat Simʿān), the ‘Fortress of Simeon’, or Deir Semaan (Arabic: دير سمعان‎ Dayr Simʿān), the ‘Monastery of Simeon’ .