Dahiya's are the descendants of the mythological sage Dadhichi, Dahiya are the ancient royal bloodlines of Jats & Rajputs.
Dahiya Jats took part in Ramayana & Mahabharata. Dahiya Jats fought with Alexandra the Great on the banks of Sutlej river. Many Jat clans today are descendants of Dahiya clan. To the Ancient Greeks they were known as DAHI, Ancient Chinese they were known as Ta-Hya. Herodotus mentions them as Great rulers of Asia, who had ancient kingdoms near Caspian sea, on the banks of Sutlej river & Russian Steppe.
Ancient Chinese traveller Fax-ian metioned that Ta-hya kingdom was pleasant and prosperous kingdom, with a numerous and flourishing population. The inhabitants all profess law, and join together in its religious music for their enjoyment. They all receive their food from the common store. Throughout the country the houses of the people stand apart like (separate) stars, and each family has a small tope [stupa]reared in front of its door. The smallest of these may be twenty cubits high, or rather more. They make (in the monasteries) rooms for monks from all quarters, the use of which is given to travelling monks who may arrive, and who are provided with whatever else they require.
The lord of the country lodged Fax-ian and the others comfortably, and supplied their wants, in a monastery called Gomati, of the Mahayana school.
Ancient writer Herodotus writes that in wars Alexander sent for Scythian Jat troops. These were mostly Dahiya Jats. With the help of these troops Alexander defeated his enemies. The Greek historian writes that these Dahiya Jats contributed a great deal to the later successes of Alexander.