"agree to" vs. "is agreed to"

[imchongjun]

Hello, teachers.
I came across the following sentence:

Servia must be punished, naturally, but to that, in principle, every nation in Europe is agreed.

and I wonder why the latter half of the sentence should not be written "but to that, in principle, every nation in Europe agrees". I appreciate very much if you could explain the difference of these two expressions.

[Shakespeare's brother]

'Every nation is agreed' and 'every nation agrees' have the same meaning. 'Is agreed' could be seen as an older but more stately form...often used by the media.

[imchongjun]

Thank you for your quick response.
That is what I wanted to know.
Thanks a ton.