The term "Solidus" refers to a gold coin that was widely used in the Roman Empire. Introduced by Emperor Constantine the Great in the 4th century, the solidus became a standard currency for trade and commerce. Its consistent weight and purity made it a reliable medium of exchange, helping to stabilize the economy during a time of great change. Over the centuries, the solidus influenced many other currencies, including the Byzantine gold coin known as the "hyperpyron." The legacy of the solidus can still be seen today in modern coins and the concept of currency stability, highlighting its importance in the history of money.