The radiance of Vivasvan, the Sun, was so intense that his brilliance scorched the three worlds, making life difficult for all beings. Vivasvan, the illustrious son of Kashyapa, was renowned as the greatest among those who burn with fiery energy. From his union with Sanjna, he fathered three children: a daughter and two sons, all destined to become lords of creatures. The first son was Manu, once known as Shraddhadeva, who became the sovereign of all beings. Alongside him, the twins Yama and Yamuna were born—Yama destined to rule over the departed, and Yamuna to flow as a sacred river. Yet, Sanjna found it impossible to endure the overwhelming radiance of her husband. Troubled by his dark and blazing form, she created from herself a perfect likeness, a shadowy double named Chhaya. This Chhaya, formed through Sanjna’s own power of illusion, stood before her with folded hands and bowed head, ready to serve. With gentle words, Chhaya asked Sanjna, “What is your will, O fair-smiling one? Instruct me, for I am here to do your bidding.” Sanjna replied, “I must go, may all be well with you, to my father’s house. You alone must remain here in my place, without fear. Care for these two boys and this slender-waisted girl as your own, but never reveal the truth to my lord at any time.” Chhaya promised, “O goddess, until I am seized by the hair or cursed, I will never disclose your secret. Salutations to you; go as you wish.” Thus assured, Sanjna entrusted her children to Chhaya, and feeling both ashamed and resolute, she set out for her father Tvashtar’s abode. Upon her arrival, her father rebuked her again and again, urging her to return to her husband. Unable to face her situation, Sanjna transformed herself into a mare and wandered north to the land of the Kurus, grazing in the grassy forests and concealing her true form. Meanwhile, Vivasvat, unaware of the exchange, believed Chhaya to be his second wife. From their union, a son was born, equal in brilliance to the Sun himself. The lord proclaimed, “He is like the elder Manu,” and so this son became known as Savarni. Another son was also born—Shani, the bringer of justice. Sanjna, in her mare form, became the mother of her own son once more. Sanjna showed greater affection for Shani than for her earlier children. Manu accepted this, but Yama did not. Angered and acting out of childishness, Yama threatened Chhaya with his foot, not knowing the truth. In her distress, Chhaya cursed him, “May your foot fall off!” Frightened by the curse, Yama hastened to his father, reporting everything with folded hands. He pleaded, “May this curse be lifted. Mothers should treat all children with equal affection. Vivasvat now favors her new son, and though I raised my foot, I did not strike her. Whether from childishness, greed, or delusion, I beg forgiveness, O Lord of the world. I have been cursed, but by your grace, may my foot not fall, O protector of cows.” Vivasvat replied, “My son, there is a great reason for your anger; you know righteousness and speak the truth. Yet, your mother’s words cannot be made false. Worms will consume your flesh and fall to the earth, thus fulfilling her curse. But the curse will be lifted, and you will be protected.” Turning to Sanjna, Vivasvat asked, “Why, among children who are all equal, do you show greater affection to one?” Sanjna, wishing to avoid revealing the truth, remained silent. But Vivasvat, steadying himself in yoga, perceived all that had happened. Desiring to curse her for her deception, the blessed Sun instead seized her by the hair. At this, Sanjna confessed everything. Angered, Vivasvat approached Tvashtar, Sanjna’s father. Tvashtar received and worshipped him, seeking to calm his wrath. Tvashtar explained, “This form of yours, radiant with excessive brilliance, is unbearable. Unable to endure it, Sanjna now wanders in the grassy forest. Today, O protector of cows, by resorting to yoga, you will see your virtuous wife, who is praiseworthy and endowed with yogic power. If you agree, I will fashion for you a form more pleasing, one that will not trouble your loved ones.” With Vivasvat’s consent, Tvashtar placed the Sun upon his wheel and reduced his brilliance, making him even more beautiful and radiant, yet gentle. Now, with his brilliance tempered, Vivasvat resorted to yoga and discovered his wife, Vaḍavā, in the form of a mare, her radiance and discipline making her unassailable. The sages saw her, fearless, roaming as a mare, and the Sun, taking the form of a horse, approached her. Sensing the approach and suspecting another male, Vaḍavā resisted union, but the Sun’s seed entered her through her nostrils. From this union were born the two Ashvins, Nasatya and Dasra, foremost among physicians and known throughout the worlds as the Ashvins. Thus, these two, the sons of Martanda Vivasvat, the eighth Prajapati, were revealed by Bhaskara in a form of great beauty.