The Insular Celts are the speakers of Insular Celtic languages; they comprise all living Celtic languages, and all of the modern Celtic nations, but the term is mostly used in reference to the peoples of the British Iron Age prior to the Roman conquest. The Insular Celtic languages spread throughout the British Isles in the course of the British Iron Age and soon split into the two major groups, Goidelic in Ireland and Brittonic in Great Britain, corresponding to the population groups of the Goidels (Gaels) on one hand and the Britons and the Picts on the other. The extent to which these peoples ever formed a distinct ethnic group remains unclear. While there are early records of the Continental Celtic languages, allowing a comparatively confident reconstruction of Proto-Celtic, Insular Celtic languages become attested in connected texts only at the end of the Dark Ages, from around the 7th century AD, by which time they had become mutually incomprehensible.