Namaskar friends.
2.Yayati, a common ancestor of lord Krishna and Arjun, had married to Devayani,the daughter of shukrachary, the guru of Danavas. Shrmistha, the princess was cursed to be dasi and had become a dasi of DEvayani.
While living as husband and wife one day Yayati and Devayani had gone to go around the garden where Sharmisth's palace was erected. Incidentally a child of Sharmistha ran unto Yayati, and saying "father! father!..." clung on his body. Devayani became furious by seeing this scene and left for her father. She narrated everything to her father and Shukracharya in turn became angry and cursed Yayati to become old and he became old.
Yayati then went to his father-in-law and pleaded Oh! father-in-law! your daughter is still young and I became old. So you have harmed to your daughter too.
Realising his mistake, then amended his curse-Any of your sons whosoever voluntarily will give his youth to you will become old and you will rejuvenate.
Devayani had four sons, first being Yadu. Yayati approached Yadu. He rfused. One by one all other sons of Devayani also refused. Then he went to Sharmistha's sons. The first was Puru and instantly he agreed to his father's request and Yayati rejuvenated and Puru became old.
regards