Although sundials have been used since the 8th century B.C., the first individual to be credited with the invention of a sundial is Aristarchus of Samos in about 280 B.C.
Aristarchus invented the hemispherical sundial, or hemicycle. It consisted of a block of stone or wood that had a hemisphere-shaped depression cut into it. A pointer was placed on one end of the depression and fixed into place. The path that the shadow followed was approximately a circular arc, hence the name. Inside the hemisphere different lines were engraved to track the path of the sun in different seasons. The hemicycle was widely used all over the world for several centuries.