Zhenwu rose to the height of his popularity during the Ming dynasty (1368-1644). The third Ming emperor, Yongle, credited Zhenwu with helping him secure the throne and ordered a massive temple-building campaign at Wudang Shan, the place where Zhenwu is believed to have attained immortality and ascended to heaven. The long, slicked-back hair and the bare feet are the two most salient indicators of Zhenwu's identity, and there are several folk legends explaining this common depiction. According to one folk legend, Yongle summoned a sculptor to the palace to commission the first image of Zhenwu. When the sculptor arrived, Yongle had just finished a bath. The emperor commanded the sculptor to create a true likeness of Zhenwu. The sculptor replied that he had never seen the god, to which Yongle replied 'look at me'. The sculptor then literally created the image of Zhenwu in the likeness of Yongle, fresh from the bath, his hair still wet and slicked back and feet bare. Another version of the story is told in the hagiography of Zhenwu published in 1602 by Yu Xiangdou. According to Yu, Zhenwu was getting ready for the day and combing his hair, when heavenly envoys arrived with the announcement of his appointment as a heavenly emperor. He accepted the appointment, and after bowing in thanks, continued to comb his hair. To his astonishment, he found that he could not put his hair up. He was then informed by the heavenly messenger that since he had already accepted his heavenly appointment, his appearance was fixed, and he could no longer change his form. Other legends tell of Zhenwu engaging in a fierce battle with demons and emerging victorious but having lost his footwear and his hair coming undone.