Brahmanisim which reasserted itself under the Guptas got further strengthened during this period. Its gradual ascendancy brought about the decline of Buddhism despite the patronage given to it by Harsha which is evident from the account of Hiuen Tsang. But Jainism did not undergo any major changes and it made neither progress nor any decay. Saivism became the main theistic system of this period. But Vaishnavism which was popular during the age of the Guptas was gradually declining during these period. The Vedic ceremonies and rituals once again came to be regarded as inseparable and integral constituents of Brahmanisim and the people practised them on a larger scale.
Nausasi Copper plate gives us information about Harsha's successful expedition against Valabhi. Madhuban plate Inscription dated 631 AD traces the genealogy of Harsha up to four generations. The Banskhera, Nalanda and Sonepat inscriptions of Harsha describe him as a worshipper of Siva. The Banskhera inscription shows that Harsha was an expert calligraphist.