The Great Epic of the Bhārata dynasty 12.200.36

12.200.36

tatra tretāyuge kāle saṃkalpājjāyate prajā |
na hyabhūnmaithuno dharmasteṣāmapi janādhipa || 36 ||

"The slayer of Madhu also created the Day and the Night, and the Season in their order, and the Morn and the Even. After reflection, he also created the clouds, and all the (other) immobile and mobile objects. Possessed of abundant energy, he also created the Viswas and the earth with all things upon her. Then the highly blessed and puissant Krishna, O Yudhishthira, once again created from his mouth a century of foremost Brahmanas. From his two arms, he created a century of Kshatriyas, and from his thighs a century of Vaisyas. Then, O bull of Bharata's race, Kesava created from his two feet a century of Sudras. Possessed of great ascetic merit, the slayer of Madhu, having thus created the four orders of men, made Dhatri (Brahman) the lord and ruler of all created beings. Of immeasurable effulgence, Brahman became also the expositor of the knowledge of the Vedas. And Kesava made him, called Virupaksha, the ruler of the spirits and ghosts and of those female beings called the Matrikas (mothers). And he made Yama the ruler of the Pitris and of all sinful men. The Supreme Soul of all creatures also made Kuvera the lord of all treasures. He then created Varuna the lord of waters and governor of all aquatic animals. The puissant Vishnu made Vasava the chief of all the deities. In those times, men lived as long as they chose to live, and were without any fear of Yama. Sexual congress, O chief of the Bharatas, was then not necessary for perpetuating the species. In those days offspring were begotten by flat of the will. In the age that followed, viz., Treta, children were begotten by touch alone. The people of that age even, O monarch, were above the necessity of sexual congress. It was in the next age, viz., Dwapara, that the practice of sexual congress originated, O king, to prevail among men. In the Kali age, O monarch, men have come to marry and live in pairs.