The Prem Sagar was one of the first books published in modern Hindi, written in the Delhi dialect which was eventually adopted as one of the official national languages of India. It is the tale of the deeds of Krishna, the invincible avatar of Vishnu. Based on the tenth book of the Bhagavata Purana, the Prem Sagar, which means Ocean of Love, (one of Krishnas epithets) was composed by Lallu Lal between 1804 and 1810.