The history of the Irish language begins with the period from the arrival of speakers of Celtic languages in Ireland to Ireland's earliest known form of Irish, Primitive Irish, which is found in Ogham inscriptions dating from the 3rd or 4th century AD. After the conversion to Christianity in the 5th century, Old Irish begins to appear as glosses and other marginalia in manuscripts written in Latin, beginning in the 6th century. It evolved in the 10th century to Middle Irish. Early Modern Irish represented a transition between Middle and Modern Irish. Its literary form, Classical Gaelic, was used by writers in both Ireland and Scotland until the 18th century, in the course of which slowly but surely writers began writing in the vernacular dialects, Ulster Irish, Connacht Irish, Munster Iris
