The Daysan River or Daisan River was the name of the river that flowed through Urfa, a tributary of the Khabur. Historically known as the Scirtus (Ancient Greek: Σκίρτος),[1] Procopius describes it as a river of Mesopotamia, a western tributary of the Chaboras (modern Khabur). It flowed from 25 sources, and ran past Edessa.