My understanding is that Latin was spoken widely in Britain at least until the Roman army evacuated in 410. How is it then that prior to 1066, aka old English Beowulf times, all Latin influence seems to have disappeared from the language?
edit: typo
hi! there's always room for more input on this, but FYI, there are a few related discussions in this section of the FAQ* - check it out for previous reponses
Why doesn't England speak a Latin-based language like other former European Roman provinces
*see the link on the sidebar or the wiki tab
You should definitely check out the link given by /u/Searocksandtrees but I just want to clear up a misconception you seem to have here about the languages involved.
Latin was spoken, apparently widely, through Britain before 410 and this seems to have continued afterwards. When Gildas wrote De excidio Britanniae, perhaps in the 540s, he wrote in a very contemporary style of Latin, presumably with the assumption that there were those in Britain who could have read it.
When the Angles, Saxon, and other Germanic peoples got there, the influence of Latin remained strong since the church dominated most literary efforts straight up until 1066 and of course beyond. A poem like Beowulf is an anomaly, since it is not written in Latin. Almost everything written in England between 600 and 1066 was written in Latin. Furthermore, since almost everyone who wrote in Old English already knew Latin, Latin had a huge influence on Old English, just like it has had on English up to the twentieth century.