During the middle ages the owl was seen as a sinister animal and seeing them/being identified with them was not something to be desired. I came across a picture of an owl in a 1624 Brussels emblem book (French/Latin) where the owl is associated with knowledge and learning. Does anyone know when the owl's association changed or does anyone have an earlier example of the owl as a sign of knowledge?
In classical Greece, the owl was a symbol of Athena, and thus of knowledge, wisdom, and Athens. It maintained this association with the Roman Minerva and through later years. You might have seen an Athenian tetradrachm like this before; it has Athena on one side and her owl on the other, with the "AΘE" abbreviation indicating it's Athenian. Plutarch tells us that an owl was a good omen for the Greeks:
Some say that while Themistocles was thus speaking upon the deck, an owl was seen flying to the right hand of the fleet, which came and sate upon the top of the mast; and this happy omen so far disposed the Greeks to follow his advice, that they presently prepared to fight.