Kay Khosrow sacrificed for Anahita in Lake Chichast for winning a chariot race. He killed Afrasiyab in  Lake Chichast as revenge for Siavash who had been killed by Aγraēraθa, son of Naru.
The passage describes Kay Khosrow's actions motivated by revenge and sacrifice in the context of a conflict involving Anahita, Siavash, and Aγraēraθa.