The things that look like bookmarks are the "seven seals" from Revelation:
And I saw in the right hand of him that sat on the throne, a book written within and without, sealed with seven seals. And I saw a strong angel, proclaiming with a loud voice: Who is worthy to open the book, and to loose the seals thereof? (Revelation 5:1-2, DRV)
You can see that the artist has drawn red wax seals on the bookmarks, although that doesn't quite make sense in terms of a modern translation:
I saw a scroll in the right hand of the one who sat on the throne. It had writing on both sides and was sealed with seven seals. Then I saw a mighty angel who proclaimed in a loud voice, “Who is worthy to open the scroll and break its seals?” (Revelation 5:1-2, NABRE)
The seals in the style of the OP can also be seen in this painting from 1806-1809 by Puerto Rican artist
José Campeche: