A Bestiary is a collection of short descriptions of all sorts of animals, wheter real or immaginary, birds and even rocks. Each one is accompanied by a moralising explanation, and has never been inteded as a scientific text, though some descriptions are fairly accurate.
The Bestiary appeard in its present form in England in the 12th century, and consisted of a compilation of earlier sources, the most important of which is the Physiologus.
The Physiologus, written in Greek by an anonymous author, comprises chapters on real and mythological animals and birds, reptiles, and magic stones. The main sources of this compilation were pre-Christian works and Church authors, the Bible, and popular fables.
Out of all the Bestiaries, the Westminster one is considered to be one of the most beautiful and richly decorated bestiaries in the world, and is full of all kinds of incredible descriptions, legends and myths.
The illuminations are on red or blue background; mostly framed, there are 164 images, decorated with snow-flakes, 3 dots, and crosses with dots. The manuscript was painted by a single very skilled artist.