Why was Athena important to Athenians?

I believe Athena was important to the Athenians because she was the founder of Athens, her city in Greece (Now the capital).

She was competing with Poseidon, the Greek God of The Sea and Earthquakes, on who should rule the city. So, they were each presented a gift for the city. Poseidon's Gift was a water spring, and Athena's gift was the Olive Tree. The people agreed that Athena's Olive Tree was better and helped the town more, so they names it after her. They worship her. That is also what created the rivalry between Athena and Poseidon.