In Srimad Bhagavatam (the treasure from which so many questions arise!), the story of Maharaja Prthu is described in the Fourth Canto, Chapters 15 to 23. In Chapters 19 and 20 is described the story of Prthu's 100 Ashvamedha Yajnas. According to this story, Prthu had performed 99 Yajnas, causing ...