Common Brittonic was a Celtic language spoken in Britain before the arrival of the Anglo-Saxons. It is part of the Brythonic branch of the Celtic languages and is the ancestor of modern languages such as Welsh, Cornish, and Breton. Common Brittonic was used by the native Britons and was prevalent until around the 7th century. The language is known primarily from place names, personal names, and a few inscriptions. As the Anglo-Saxon influence grew, Common Brittonic gradually declined, leading to the fragmentation of the language into its descendant forms. Today, it is studied for its historical significance and influence on the development of English and other regional languages.