Featured Verify authenticity of 15th century illuminated vellum manuscripts?

Hello. can any experienced collectors take a look at these two purported illuminated vellum 15th century manuscripts from a book of hours? the first two and the latter two are different products. Any help is appreciated! Thank you.

 

Seems very interesting

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I wonder a bit about the pencil writing. are they from a library ?

 

The one with the brown toning is in a private collection. I had a question, is the lighter paper also written in Latin? I know the toned manuscript is in latin

 

Not sure, but the lighter one does look like Latin to me. Maybe somebody more knowledgeable will drop by.

 

Both are Latin, the pencil writing is most likely the Lot number/ Auction number from an auction house.