This is inevitable when money isnt made of gold or silver;...Gold and silver coinage is as valuable in one country as the next.
Henry VIII made his “silver” coins more and more out of copper to the point of where his portrait’s nose started to look copperish. And after WWI Britain issued silver coins not in sterling (.925) but rather 50%. After WWII they went to copper nickel as did we in 1965.
Even Byzantium did that - but people could tell. Instead of five pieces of silver, something just cost ten new pieces of “silver”.