According to Harsha-Charita, a royal line was founded by one pushyabhuti, a devout Saivite, some where near Thaneswar in the Ambala district of Haraya. Nothing much is known about this ruler. It was only the fourth ruler prabhakaravardhana that the title Maharajadhiraja was assumed. Historians surmise that like the Maukharis, their immediate neighbour in the east, the Pushyabhutis took advantage of the fall of the Gupta empire to find an independent principality.
A few details of Prabhkarvardhana are to be found in Harshacharita. He was the great General, who possibly defeated the Hunas also. Bana also mentions that he was the devotee of the sun.
Prabhakaravardhana had two sons, Rajhavardhan and Harshavardhana and one daughter, Rajyasri. Grahavarman of the Maukhari dynasty was married to Rajyasri.
After the death of Prabhakaravardhan, Rajyavardhan ascended the throne. Soon had news came, Grahavarman was killed by the Malwa ruler. Rajyavardhan leaving the kingdom toteh care of Harshavardhan, went after the Malwa army. The Malwa king was defeated and possibly killed. On his return Rajyavardhana was confronted by Sasanka. All the available authorities declare that Rajyavardhana was killed by Sasanka throught they differ in details. After his death, harsha succeeded to the throne of Kanauj with the title of Rajputra and style of Siladitya.
However, the inscriptions of Harsha mention the names of only four of his immediate ancestors. The kingdom was founded by Naravardhana about the close of the fifth or beginning of the sixth century A.D. His grandson Adityavarman was known for marrying a sister of the later Gupta monarch Mahasena-Gupta. It was only under Prabhakaravardhana, the kingdom grew both in territory and influence as he is the first to be styled maharajadhiraja. The Harishcharita calls him a lion to the Huna deer, a burning fever to the king of sind a troubler of the sleep of Gurjara a bilious plague to that scent-elephant, the lord of Gandhara, a looter of the lawlessness of Late and an axe to the creeper of Malwa's glory.