As late as 1750, how much of Prussia, the largest German state, did the king own?
Answer: Around a third. If one was to equate this to modern times, it would not be too fanciful to suggest that this was equivalent to the King of Prussia owning a third of Germany’s gross national product of US$3 trillion, giving the king an equivalent income of perhaps US$1 trillion a year.
Source: A History of the World by Hugh Thomas