The above success, however, proved to be the immediate cause of conflict
  between Harsha and Pulakesin II. Further, the question of overlordship
  over the Latas, Malwas and Gurjaras seems to have been the long-standing
  cause of conflict between the two. Hiuen Tsang gives an elaborate
  description of Harsha’s preparations for this war, but does not talk about
  its result. However, he gives the impression that Harsha was the aggressor
  but did not succeed fully in the war. Chalukyan records of Pulakesin’s
  successors mention the defeat of Harsha by Pulakesin. Ravi Kirti (the
  court poet of Pulakesin II and the author of the Aihole Inscription) also
  hints vaguely at Pulake- sin’s victory. But Ravi Kirti’s account as well as
  the records of Pulakesin’s successors cannot be taken as impartial as none
  of the contemporary records refer to Pulakesin’s victory over Harsha. So
  the only thing we can say is that Harsha’s attack was not a complete
  success, and it resulted in the conclusion of an honourable treaty with
  Pulakesin, who continued to have his sway over the south.
His Other Conquests According to some scholars, Hasha defeated the
Pallava ruler, Mahendravarman I, and also some other southern rulers. But in
the absence of any direct evidence, we cannot say anything conclusively. But
Orissa or the kingdom of Kalinga seems to have been subjugated by Harsha.
Thus, Harsha established his hold practically over the whole of north India.
Rajasthan, Punjab, UP, Bihar and Orissa were under his direct control but his
sphere of influence spread over a much wider area since peripheral states
such as Kashmir, Sind, Valabhi and Kamarupa acknowledged his
Harsha’s Government
Harsha governed his empire on the same lines as the Guptas did, except that
his administration had become more feudal and decentralised. It is stated· that
Harsha had cavalry numbering over one lakh and 60,000 elephants. This
seems to be astonishing because the Mauryas, who ruled over practically the
whole of the country, maintained only 30,000 cavalry and 9,000 elephants.
Harsha could possess a larger cavalry only if he could mobilise the support of
all his feudatories at the time