https://en.wikipedia.org/wiki/Las_M%C3%A9dulas
When the Eastern Roman Emperor Anastasius died in 518, he left 23,000,000 gold solidi (320,000 pounds of gold or 420 long tons) in the treasury.
Used to be Byzantine gold coins were relatively cheap, because they are still plentiful. Or rather, were plentiful, I’d guess a lot of surplus were processed into numbered bars during the early years of gold as a commodity.