Hyperpyron of Alexios I

A hyperpyron gold coin struck in Constantinople, 1092–1118. In the 11th century, the fineness of the nomisma began to decline from the 1030s, and by the 1070s–1080s, its gold content had dropped to almost zero. In 1092, Alexios I Komnenos completely reformed the coinage system, introducing the hyperpyron, meaning "highly refined." Its weight was the same standard as the solidus, and its fineness was 20.5 carats. It served to rebuild the economy as the empire's standard gold coin, replacing the old, discredited currency. This is a piece struck in the name of the reformer himself, and it is housed in the Moscow Kremlin Museums.