“With scant respect for priorities, the Germanic invaders called the native Celts wealas (“foreigners”), from which the name Welsh is derived. The Celts called the invaders “Saxons”, regardless of their tribre […]. By the end of the 6th century, however, the term Angli (“Angles”) was in use – as early as 601, a king of Kent,Æthelbert, is called rex Anglorum (“King of the Angles”) – and during the 7th century Angli or Anglia (for the country) became the usual Latin names.Old English Engle derives from this usage, and the name of the language found in Old English texts is from the outset referred to as Englisc […]. References to the name of the country as Englaland (“land of the Angles”), from which came England, do not appear until c. 1000.”
The Cambridge Encyclopedia of the English Language
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