The Anglo-Saxons refers collectively to the groups of Germanic tribes who achieved dominance in southern Britain from the mid-5th century forming the basis for the modern English nation.
The term "Anglo-Saxon" goes back to the time of King Alfred, who seems to have frequently used the title rex Anglorum Saxonum or rex Angul-Saxonum. The origin of this title is not quite clear. It is generally believed to have arisen from the final union of the various kingdoms under Alfred in 886. Bede (Hist. Eccl. i. 15) states that the people of the more northern kingdoms (East Anglia, Mercia, Northumbria, &c.) belonged to the Angli, while those of Essex, Sussex and Wessex were sprung from the Saxons, and those of Kent and southern Hampshire from the Jutes. Other early writers, however, do not observe these distinctions, and neither in language nor in custom do we find evidence of any appreciable differences between the two former groups, though in custom Kent presents most remarkable contrasts with the other kingdoms. Still more curious is the fact that West Saxon writers regularly speak of their own nation as a part of the Angelcyn and of their language as Englisc, while the West Saxon royal family claimed to be of the same stock as that of Bernicia. On the other hand, it is by no means impossible that the distinction drawn by Bede was based solely on the names Essex (East Seaxan), East Anglia, &c. We need not doubt that the Angli and the Saxons were different nations originally; but from the evidence at our disposal it seems likely that they had practically coalesced in very early times, perhaps even before the invasion. At all events the term Angli Saxones seems to have first come into use on the continent, where we find it, nearly a century before Alfred's time, in the writings of Paulus Diaconus (Paul the Deacon). There can be little doubt, however, that there it was used to distinguish the Teutonic inhabitants of Britain from the Old Saxons of the continent.