The Lydian Kingdom made Sardis its capital as early as 700 B.C. Lydians were known to be very successful and creative in the fields of commerce and economics. Sardis was ruled by Alexander the Great in the 4th century B.C., and then by the Roman Empire in the 2nd century B.C. The first king of Sardis was Gyges (687-652 B.C), credited with the invention of the first coined money. The last and most famous Lydian King, Croesus (560-546 B.C.), was said to have panned gold from the nearby river Pactolus and introduced coinage of pure gold and pure silver. The king Croesus was the wealthiest man of his time and Sardis became the richest city of antiquity. Sardis lies in the territory of Lydia, at the foot of the Tmolus Mountains, overlooking the Hermus River plain, where evidence has been found of human activity as early as the Palaeolithic period (ca. 50,000 B.C.). The site of Sardis (modern Sart) lies some 60 miles east of Izmir, along the Izmir-Ankara highway.