After Athens and Sparta joined to defeat Persia did they remain allies?

No, after defeating Persia, Athens and Sparta did not remain allies. Their cooperation during the Persian Wars was primarily driven by a common enemy, but once that threat was eliminated, tensions arose due to differing political systems and ambitions. This rivalry eventually led to the Peloponnesian War, a protracted conflict between the two city-states. The discord highlighted the fragility of their alliance and the challenges of maintaining unity in the face of diverging interests.