I just wrote 'Britain Isle', but I am not sure if that is the correct name for it. Aren't the modern day Englishmen the Saxons which once lived in Northern Germania?
We don't know who they were because the first inhabitants of the British Isles were the Palaeolithic hunter gatherers that populated much of Europe. It wasn't until the 6th Century AD that the Saxons, Jutes and the Angles settled in Britain, ultimately becoming the 'Anglo-Saxons'. However, the British isles have always been a place of historical immigration; Roman, Norman, Saxon, Viking for example.
FYI
but I am not sure if that is the correct name for it
The correct name for the main island is 'Great Britain'. If you include Ireland and all the smaller islands (eg Isle of Man, the Hebrides etc) the name you would use would be the 'British Isles'.