What is that which is due to a sovereign, as a seigniorage on gold and silver coined at the mint, metals taken from mines, etc.; the tax exacted in lieu of such share; imperiality called?

royalty — That which is due to a sovereign, as a seigniorage on gold and silver coined at the mint, metals taken from mines, etc.; the tax exacted in lieu of such share; imperiality. (Webster's 1913.)