ABSTRACT
Zhenwu was originally Xuanwu. To avoid the personal name of the [imperial] Holy Patriarch [which contains the word xuan,] he is therefore called Zhenwu. … The shapes of the constellations Xu and Wei [in the northern sky] are similar to the snake and the turtle, therefore the north is referred to as Xuanwu of the seven stars.… At present, people take Xuanwu to be a perfected saint and make [images of a] real turtle and snake beneath him. This is ridiculous enough. In addition, they added the perfected lords of Tianpeng, Tianyou, and Yisheng [with Zhenwu] to form the Four Saints.
