Yaduvanshi are the descendents of King Yayati’s son Yadu. Yadu is the one of the five Indian tribe known as Panchajana or Panchakrishtya mentioned in the Rig Veda.
Origin Story Of Yaduvanshi:
- Origin of Yaduvansh start with story of Yadu’s father King Yayati.
- King Yayati was son of King Nahusha & Ashokasundri , Ashokasundri was daughter of Lord Shiva & Parvati. Yayati father, Nahusha is transformed into a snake by curse uttered by the sages as punishment for his arrogance.
- Yayati’s elder brother, Yati is initially given the kingdom, but Yati turns it down & becomes an ascetic. Yayati then becomes king in his place and prospers so greatly that he is able to conquer the world. He appoint his four younger brother to rule the world’s candinal directions.
- One day Sharmishta (daughter of King Vrishparva) and Devayangi (daughter of Aasura guru Shukracharya) go with Sharmishta’s retinue to bath in a forest pool not far from their home.
- After bathing, Sharmishta confuses Devayani’s Sari with her and put it on instead. Devayangi in return, scolds Sharmishta for her mistake and belittles her with the jibe that she is the daugther of Aasura Guru Shukracharya as Vrishparva’s and their Kingdom lives on his blessings. The slur on herself and her father Vrishparva infuriates, Sharmishta. With the help of her servents, Sharmishta throws the naked Devayangi into a well and leaves the forest with her retine. Later King Yayati come to well for water and help Devayangi to climb out of it. 
- Devayangi resolves to make Sharmishta her servant in revenge for trying to kill her by throwing her into the well. Sharmishta’s father, Vrishparva agrees to this, since he fears that the continued security of his kingdom would be in doubt without the sage counsel of Shukracharya. Sharmishta also agrees to this to save the kingdom and becomes Devayangi’s maid servant.
- Some days later Devayangi goes on a picnic in the forest with her servants (including Sharmishta). There she again meets Yayati, who is out hunting. Yayati finds himself attracted by Sharmishta’s beauty, asks Devayangi about her. Devayangi observed this, introduced Sharmishta as her slave and also claimed that he should become her husband as he has held while helping her out of the well Yayati fears Shukracharya, and tells. Devayangi that he will marry her only if his father agrees.
- This time she brings him to her father and tells him that she would like to marry Yayati. Shukracharya gives his consent and tells Yayati that she would like to marry Yayati. Shukracharya gives his consent and tells Yayati that he should take care of Sharmishta too (as she is a princess, by birth) although he shouldn’t maintain a physical relationship with her. Yayati marries Devayani and looks after her well.
- After a long while, Sharmishta comes to Yayati and requests him to give her a child. He refuses and say that, if he were to do so, he could not face the wrath of Shukracharya. Nevertheless, Sharmishta manages finally to convince him, saying that it would be against Dharma if were to refuse her request; he being the king, it is his responsiblity to ensure the needs of the citizens and she is desperate to have a child. He reluctanly agree and they begin a relationship, in the hopes that she will conceive. In due course, Devayani gives birth to two sons Yadu and Turvasu while Sharmishta be gets three sons Druhyu, Anu and Puru.
- Eventually Devayani learns of her husband’s affair with Sharmishta and complains to her father. Enraged at his son-in-law’s disobedience, Shukracharya curses Yayti with premature old age in punishment for inficting such pain upon his daughter. However on learning Sharmishta’s desire to become mother, he later relents, telling Yayati that if he can persuade one of his sons to swap ages with him, he will be able to escape the curse and regain his lost youth for a while.
- Yayati asks his sons if one of them will give up his youth to rejuvenate his father, but all refuse except the youngest son, Puru (one of his sons by Sharmishta). In grateful recognition of Puru’s filial devotion, Yayati make Puru as his legitimate heir and King of his dynasty.
- Since Yadu refused to exchange his years of youth with his father Yayati. So he was cursed by Yayati that none of Yadu’s progency shall possess the dominion under his father’s (Yayati) command. 
- Thereby, he (Yadu) could not have carried on the same dynasty, called Somavanshi (or Chandravanshi). No tably, the only remaining dynasty of King Puru was entitled as Somavanshi (or Chandravanshi)
- Thereby King Yadu ordered that future generations of his would be known as Yadav and dynasty would be known as Yaduvanshi.
Several castes and communities in modern India, such as Yadav or Ahir (Ayar), Ahar Chudasama, Jadeja Rajput, Bhatti Rajputs,Jadaun Rajput, and the Sainis of Punjab Province, claim descent from Yadu.
1. The Holy Puranas. Pg 152 by Bibek Debroy, Dipavali Debroy(2002)
2. The Mahabharata of Krishna- Dwaipayana Vyasa, Book 1: Adi Parva by Kisari Mohan Ganguli, translation(1883-1896)
3. Ancient Indian Social History: Some Interpretations. Pg 268-269 by Romila Thapar