Who is the goddess of war and she lost the contest?

The goddess of war in Greek mythology is Athena. She lost a contest to Poseidon for the patronage of the city of Athens, where Poseidon offered a saltwater spring while Athena provided the olive tree. The Athenians ultimately chose Athena's gift, leading to her becoming the city's patron and protector. This contest reflects their values of prosperity and peace over military might.