Actually, as demonstrated in this lovely graphic, you'll see that the name Britain is far older than the Norman invasion, and even older than the Roman invasion of Britain! And its the "United Kingdom of Great Britain and Northern Ireland" so using that name to refer to the big island is wrong.

This however mate

Pentiment such a joyful experience to play for me, and set in a part of history I knew so little about that I couldn't help but buy this magazine for some airport reading to learn and continue the Pentiment experience!