The Andesite Sun Stone of Sarmizegetusa Regia seems to have been used as a sundial. This idea is supported by known influences on Dacian culture from Hellenistic Greece, influences which may have included ideas about geometry and astronomy.
Sarmizedetusa Regia was the capital and the most important military, religious and political centre of the Dacians. Erected on top of a 1,200 metre high mountain, the fortress was the core of the strategic defensive system in the Orăştie Mountains (in present-day Romania), comprising six citadels. Sarmizegetusa Regia was the capital of Dacia prior to the wars with the Roman Empire.