Laurus nobilis
In ancient Greece, the laurel ("Laurus nobilis") was sacred to Apollo, and as such, sprigs of it were fashioned into a crown or wreath of honor for poets and heroes. This symbolism has been widespread ever since. "Laureate letters" in old times meant the dispatches announcing a victory; and the epithet was given, even officially (e.g. to John Skelton) by universities, to distinguished poets.