Both Syriac Christianity and the Eastern Aramaic language came under pressure following the Arab Islamic conquest of Mesopotamia in the 7th century, and Assyrian Christians throughout the Middle Ages were subjected to Arabizing superstrate influence. The Assyrians suffered a significant persecution with the religiously motivated large scale massacres conducted by the Muslim Turco-Mongol ruler Tamurlane in the 14th century AD. It was from this time that the ancient city of Assur was abandoned by Assyrians, and Assyrians were reduced to a minority within their ancient homeland.