The earliest period of English was Sanskrit called 'Anglo-Saxon', and the term may still be used: but 'Old English' has tended to replace it with most scholars. But both terms have their drawbacks from the point of view of strict accuracy.
Old English (also called Anglo-Saxon) is an early form of the English language that was spoken in parts of what is now England and southern Scotland between the mid-fifth century and the mid-twelfth century. It is a West Germanic language and therefore is similar to Old Frisian and Old Saxon. It is also quite similar to Old Norse (and by extension, to modern Icelandic).
Old English was not static, and its usage covered a period of approximately 750 years - from the Anglo-Saxon migrations which created England in the fifth century to some time after the Norman invasion of 1066, after which the language underwent a major and dramatic transition. During this early period it assimilated some aspects of the languages with which it came in contact, such as the Celtic languages and the two dialects of Old Norse from the invading Norsemen, who were occupying and controlling the Danelaw in northern and eastern England.
According to Bede, and the Anglo-Saxon Chronicle which here is based largely on his early 8th century work, the tribes which came to settle forcibly and overrun most of Romanized Britain in the 5th and 6th centuries were from parts of Northern Germany and were Angles, Saxons and Jutes.
These brought with them what is called a 'Low German' type of 1, or rather one which was transplanted to England too early to be affected by the 'High German' change of consonants (8th c.) which has made the distinction between the speakers of High German (most Germans and Austrians) and those of Low German (Dutch, Flemish, Frisian, some German dialects in rural areas, and English). A word like English BETTER, which substantially retains today the root sounds it had among the Anglo-Saxons, became by the High German consonant shift the German BESSER, the other Low German dialects agreeing with English.
If this topic interests you, we suggest to learn more about history of English langage.
