In ancient Greek mythology, the goddess Athena kept an owl on her shoulder that revealed truths to her and represented wisdom and knowledge. In some versions of the mythology, the owl was said to illuminate Athena's "blind side," allowing her to see the entire truth. Owls were widely associated with Athena's blessing, and Greek soldiers viewed the sight of owls before a battle as a symbol that the goddess was on their side.
While the owl eventually came to represent Athena's wisdom, knowledge and "inner light," there are several theories regarding the development of the association between the goddess and the bird. According to several historical records, a small species of owl was common in Athens at the time, and historians have proposed that the birds' presence gave rise to the idea that they symbolized the city's goddess.
The symbol of Athena's owl was eventually used on currency within the city: Athenian tetradrachms commonly had a symbol of the owl on their reverse side. The owl was also commonly featured in Athenian art, such as vases, and the symbol eventually spread to other Greek city-states. The image of the owl as a symbol for wisdom continued in Ancient Rome as well, when owls were associated with the goddess Minerva.