A bestiary (Latin: bestiarium vocabulum) is a compendium of beasts. Originating in the ancient world, bestiaries were made popular in the Middle Ages in illustrated volumes that described various animals and even rocks. The natural history and illustration of each beast was usually accompanied by a moral lesson. This reflected the belief that the world itself was the Word of God and that every living thing had its own special meaning. For example, the pelican, which was believed to tear open its breast to bring its young to life with its own blood, was a living representation of Jesus. Thus the bestiary is also a reference to the symbolic language of animals in Western Christian art and literature. Source: Wikipedia (en)