Aditya (sun) was born to Aditi ,the daughter of Daksha prajapati.Aditya was married to Sangya devi ,daughter of Tvashtrva (architect of devatas).Sangya was very beautiful and Sun was very happily living with her. However Sangya finding the heat of Sun as unbearable , one day went back to her father’s house. Father assured that he would reduce the brilliance of his son inlaw in due course ,but it is not wise of chaste woman to leave their husband. So Sangya returned and carried on with Sun, givimg birth to Manu , Yama,and Yami.
But unable to bear Sun’s brilliance , Sangya created her replica ,Chayadevi [who resembled her in appearance] ,went away to forest in Uttara Kuru in the disguise of Mare [female horse] .Chayadevi serving Sun as Sangya (his wife), within one year gave birth to Manu,Sani and Tapti.
However Chaya grew partial towards Sangya’s children and Yama noting this complained to Father . Father showed discern towards Chaya . Chaya out of anger Cursed Yama ,” You lord over the dead ” and to Yami as ” You be a river (yamuna)” . Sensing mother never curses her child , Sun suspected Chaya . Then He found out the truth and cursed Saturn ” You become lame and cruel planet” , Tapati to become the river.
Sun out of his Divyadrishti found out Sangya was roaming in the forest of Kuru as mare , he took the form of Horse and lived with her again in the forest .Thus were born two beautiful horses(twins) Ashwini. Bramha came to the forest and appointed the Ashwini as Physicians of Devatas and offered them a boon of being extremely handsome .
Vishwakarma then prayed Aditya and subsequently he reduced his brilliance to accomodate the growth of civilization on the earth .
This story also gives the philosophical reason behind the results of Sun in seventh house.Sun in seventh house invites seperation from husband in a woman’s horoscope. Sometimes husband abandons the lady. In some cases lady has to compromise as second wife.
Thus this story of birth of Ashwini devatas, narrated by Vyasa ,brings beauty and health to those who listen or reads it.