King Janamejaya initiated the Sarpa Satra to avenge his father, Parikshit’s death, who had been bitten to death by Takshaka. The sacrifice was to ensure the destruction of all snakes and was started, but was not completed.
A learned sage named Astika, whose mother, Manasa was a Naga and father was Jaratkaru, a Brahmin came and advised Janamejaya to stop the sacrifice. The king relented and set Takshaka free. Since then the day has been commemorated on Shukla Paksha Panchami in the month of Shravan and is since celebrated as the festival of Nag Panchami.
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