An even more valuable forgery is the Donation of Constantine[1], which purported to transfer title to large parts of western Europe.<p>[1] <a href="https://en.wikipedia.org/wiki/Donation_of_Constantine" rel="nofollow">https://en.wikipedia.org/wiki/Donation_of_Constantine</a>
This article is a pretty good overview of what it's like to play Crusader Kings III, in case the minutiae of succession types, fabrication of claims, and Holy Roman Empire shenanigans sounds fun to you.
It wouldn't have required this, since, who would have dared to decline the proven heir of Heracles and Julius Caesar their rightful claim? :-)<p>(Rudolph IV substantially upgraded the genealogical claim from the 1st century Roman family of Colonna to Julius Caesar proper.)