It is not known how many Anglo-Saxons actually came to Britain between the 4th and 6th century AD. Many sources say large numbers of Anglo-Saxon settlers arrived. Because of this, some of the native Britons moved west, towards Wales and Cornwall. Others went to Armorica and became the Bretons. The language of the Anglo-Saxons, Old English, became the main language in southern Britain. A few Celtic and Latin words were borrowed into Old English.