Ceretic Guletic of Alt Clut was a king of Alt Clut  (modern Dumbarton) in the 5th century. He has been identified with Coroticus, a Britonnic warrior addressed in a letter by Saint Patrick. Of Patrick's two surviving letters, one is addressed to the warband of this Coroticus. Bemoaning the capture and enslavement of newly Christianised Irish and their sale to non-Christians, Patrick includes the imprecation:

Soldiers whom I no longer call my fellow citizens, or citizens of the Roman saints, but fellow citizens of the devils, in consequence of their evil deeds; who live in death, after the hostile rite of the barbarians; associates of the Scots and Apostate Picts; desirous of glutting themselves with the blood of innocent Christians, multitudes of whom I have begotten in God and confirmed in Christ.