Complex sentence: Assigning ethnic labels such as "Anglo-Saxon" is fraught with difficulties, and the term itself only began to be used in the 8th century to distinguish "Germanic" groups in Britain from those on the continent.
Split into simpler sentences: Assigning ethnic labels such as "Anglo-Saxon" is fraught with difficulties. This term began to be used only in the 8th century to distinguish the "Germanic" groups in Britain from those on the continent.