King Cecrops, who was half man and half snake, ruled the Attic Peninsula of Greece for a reign of 50 years. He was a legendary king who had introduced marriage, ceremonial burials, reading and writing to his people. King Cecrops built such a beautiful capital city that Zeus decided it best to have a patron to protect it.
Poseidon and Athena competed fiercely for this prestigious assignment. They were to both present gifts to the people, who would vote for the best patron saint. Poseidon struck a rock on the acropolis with his trident and created a salt sea. Athena seeded the first olive tree that instantly grew upon the acropolis.
The people voted and Athena won with her gift of the first olive tree. The city was called Athens and became the capital of Greece. Athena became the patron and protector of Athens and the city continued to flourish until modern times. All the olive trees in the city are said to be planted by Athena herself.
Athens is one of the oldest cities in Europe that has been continuously in habited since the bronze age. Some even say that it has been inhabited continuously for the last 7,000 years. Some ancients might even attribute this success to Athena’s gift of the first olive tree.
Source: Greek Mythology