Making some searches I came through different legends which tell about the origin of the famous genoese sauce, popular throughout the world.
Legends about the origin of Genoese Pesto Sauce:
According to a legend dating back centuries, Genoa’s sailors would borrow a tiny token of their beloved city to keep them company during long, lonely months at sea: a fragrant pot of basil, which they would store in their cabins. In return, wives and lovers back home would place basil plants on their windowsills until their partners returned home safely from their voyages. This practice evolved—again, according to local lore—to the point that sailors began to grind basil leaves into a tasty green sauce and travel with it because of its long shelf life.
Then, another legend says that one day, a ligurian peasant decided to prepare for her husband, who was a sailor, a sauce made of garlic and parsley to spread on bread during his long time at sea, away from home. But, that day she saw that she had little parsley in her garden, so she thought to prepare the sauce using the basil leaves. It is said that the result was amazing and the green sauce had success among all the sailors!
If you believe that legends are story alleged to be true, then you know how pesto was born.
**There is a saying that he who eats pesto never leaves Genoa**