[skyyler]

The comment you are replying to likely meant Britain, not England.

https://en.wikipedia.org/wiki/Roman_Britain

USAmericans tend to say "England" interchangably with "United Kingdom", "Great Britain", and "The British Isles". Possibly more.

[tsimionescu]

It's not just US people who do this, it's many others in Europe and around the world. The common name of the UK in many languages is some variant of England, even to the point of what you'd learn in a geography class.

Also, people very commonly use the name of modern day countries to refer to their territory, such as "most of Germany was frozen over in the last Ice Age". I suspect this is what is happening here.