Roman Empire collapses. Rome sacked by Goths. A.D. First Germanic tribes arrive in England. These dialects are distantly related to Latin, but also have a sprinkling of Latin borrowings due to earlier cultural contact with the Romans on the continent. By 600 A.D., the Germanic speech of England comprises dialects of a language distinct from the continental Germanic languages.
Supremacy passes from one kingdom to another in that order.
600 Christianity introduced among Anglo-Saxons by St. Augustine, missionary from Rome. Irish missionaries also spread Celtic form of Christianity to mainland Britain. 793 First serious Viking incursions. Lindisfarne monastery sacked. 840s-870s Viking incursions grow worse and worse.