 In this period of history, the Circassians were Christians; Islam did not begin to penetrate Circassia until the following century.In the 1560s Ivan and Temryuk directed forts to be constructed, including Tumnev at the western end of Circassian lands and at Sunzha Ostrog at the mouth of the Sunzha river, at the eastern end of Circassian lands in Kabardia.Russia thereafter left the region alone except for the Caspian coast.