Excavations at a mound known as Topraktepe indicate Hittite settlement in the area as early as 2600 BC, though little is known of Sivas’ history prior to its emergence in theRoman period. In 64 BC as part of his reorganization of Asia Minor after the Third Mithridatic War, Pompey the Great founded a city on the site called “Megalopolis”. Numismatic evidence suggests that Megalopolis changed its name in the last years of the 1st century BC to “Sebaste”, which is the feminine form of the Greek name corresponding to Augustus. The name “Sivas” is the Turkish version deriving from the name Sebasteia, as the city was known during late Roman empire. Sebasteia became the capital of the province of Armenia Minor under the emperor Diocletian, was a town of some importance in the early history of the Christian Church; in the 4th century it was the home of Saint Blaise and Saint Peter of Sebaste, bishops of the town, and of Eustathius, one of the early founders of monasticismin Asia Minor. It was also the place of martyrdom of the Forty Martyrs of Sebaste, also 4th century. Justinian I had a fortified wall around it rebuilt in the 6th century.
The city came under the domain of Turkmen Danishmend dynasty (1155–1192) after theBattle of Manzikert in 1071. After the death of Danişmend Gazi, Sivas passed to Nizamettin Yağıbasan who won it after a struggle with Danişmend Gazi’s successors. In 1174, the city was captured by Seljuk ruler Kilij Arslan II and periodically served as capital of the Seljuk empire along with Konya. Under Seljuk rule, Sivas was an important center of trade along the silk road and site of a citadel, along with mosques and madrasahs (Islamic educational institutions), four of which survive today and one of which houses the Sivas Museum. Then it passed to the Ilkhanids
The city was acquired by Ottoman Sultan Bayezid I (1389–1402). In 1398, Tamerlane swept into the area and his forces destroyed the city in 1400, after which it was recaptured by the Ottomans in 1408. Under the Ottomans, Sivas served as the administrative center of the province of Rum until about the late 19th century.