harsha or harshavardhana () or "harsha vardhan" (590–647) was an indian buddhist emperor. he ruled north-central and east india for fifty seven years. he was the son of prabhakar vardhan and younger brother of rajyavardhan, a king of thanesar. at the height of his power he ruled the gujarat, bengal, orissa and the entire gangetic plain north of the narmada river. after the downfall of the gupta empire in the middle of the sixth century c.e., north india reverted back to small republics and small monarchical states.