What is "urizen"

In the complex mythology of William Blake, Urizen is the embodiment of conventional reason and law. He is usually depicted as a bearded old man; he sometimes bears architect's tools, to create and constrain the universe; or nets, with which he ensnares people in webs of law and conventional society. Originally, Urizen represented one half of a two-part system, with him representing reason and Los, his opposition, representing imagination. In Blake's reworking of his mythical system, Urizen is one of the four Zoas that result from the division of the primordial man, Albion, and he continues to represent reason. He has an Emanation, or paired female equivalent, Ahania, who stands for Pleasure. In Blake's myth, Urizen is joined by many daughters with three representing aspects of the body. He is also joined by many sons, with four representing the four elements. These sons join in rebellion against their father but are later united in the Last Judgment. In many of Blake's books, Urizen is seen with four books that represent the various laws that he places upon humanity.