1722 Engraving From Scotland

I picked up this engraving today at an estate sale. It was one of those "Rockstar" days, I got 12 pieces of artwork for $67. (I will post some others) I would like some help figuring out what this engraving is. I just kind of assumed it was taken from a book, but I am not sure. It also looks like some type of official document. I think you should be able to read the writing. The person who's estate it was, had relatives that owned the framing shop. Thanks in advance and let me know if you need better pictures.

 

You may have figured out already that the text refers to this man:
https://en.wikipedia.org/wiki/Alexander_Hume-Campbell,_2nd_Earl_of_Marchmont

The Wikipedia article says that he was ambassador the the Congress at Cambray in 1722. I see the word "Cambray" and the date of 1722 on your document, and it probably has something to do with that. The coat of arms relates to his family. https://commons.wikimedia.org/wiki/File:Purves_6th_baronet_ex-libris.jpg

The University of Illinois has a digitized copy of what looks like the same document on their website: https://digital.library.illinois.edu/items/4197a0a0-3fcc-0134-1da0-0050569601ca-7#?c=0&m=0&s=0&cv=0&r=0&xywh=-2349,173,7302,3703

I did not closely compare yours with theirs. Their caption says it is a bookplate.

 

That makes sense, it would have been attached to the inside of the front covers of his books. Mine must have been peeled off.