The history of the area that now constitutes Himachal Pradesh dates back to the time when the Indus valley civilisation flourished between 2250 and 1750 BCE.[11] Tribes such as the Koilis, Halis, Dagis, Dhaugris, Dasa, Khasas, Kinnars and Kirats inhabited the region from pre-historic era. During the Vedic period, several small republics known as "Janapada" existed which were later conquered by the Gupta Empire.[12] After a brief period of supremacy by king Harshavardhana, the region was once again divided into several local powers headed by chieftains, including some Rajput principalities.