The Cambrai Homily is the earliest known Irish homily, dating to the 7th or early 8th century, and housed in the Médiathèque d'agglomération de Cambrai. It is evidence that a written vernacular encouraged by the Church had already been established alongside Latin by the 7th century in Ireland. The homily is also the oldest single example of an extended prose passage in Old Irish. The text is incomplete, and Latin and Irish are mixed. Quotations from the Bible and patristic sources are in Latin, with the explication in Irish. It is a significant document for the study of Celtic linguistics and for understanding sermons as they might have existed in the 7th-century Irish church. The homily also contains the earliest examples in written Irish of triads, a form of expression characteristic of