John Gill Commentary Ezra 4:11

"This is the copy of the letter that they sent unto Artaxerxes the king: Thy servants the men beyond the River, and so forth." — Ezra 4:11 (ASV)

This is the copy of the letter they sent to him, even
to Artaxerxes the king
Which Ezra brought with him from Babylon, and is contained in the five following verses:

your servants the men on this side the river, and at such a time ;
this was the inscription of the letter, or the beginning of it.