Chinese history abounds with legends about the planning and building of imperial cities, but none are as fanciful as those about Ta-tu, the "Great Capital" of the Mongol-Yüan state and predecessor of Peking, the majestic capital of the Ming and Ch'ing. Ta-tu, which Marco Polo called Cambaluc ("city of the Khan"), was built in the Yen province under Khubilai Khan in 1267-83. The city was designed by the great khan's chief adviser Liu Ping-chung (1216-74), a Buddho-Taoist adept in astronomy, mathematics and the pseudo-sciences. Many legends about the building of Ta-tu grew out of Liu Ping-chung's ingenious designs for the capital. These legends were further embroidered with popular beliefs about the dragon genii who inhabited the lakes and rivers and controlled the water resources of the region. Two noteworthy references to the legends surrounding the building of Ta-tu are contained in literary collectanea dating from the late Yüan and early Ming. The first is to be found in one of a set of poems on the capital entitled "Nien-hsia ch'ü" by the belle lettrist Chang Yü, which says: There are eleven gates around the walls of Ta-tu, thatched with hay and paved with earth the Na-cha city was built. The prophecy says if [the walls] were encased in brick and stone, they will be as long as [the column of] the armored soldiers of the Heavenly King. The other, recounted by Ch'ang-ku chen-i (pseudonym) in his miscellany Nung-t'ien yü-hua, offers this: The city of Yen was designed by Liu T'ai-pao [Liu Ping-chung]. There are eleven gates in order to symbolize Na-cha's three heads, six arms and two feet. Shih-tsu [Khubilai Khan] was enthroned in the keng-shen year [1260], and the state perished between the wu-shen [1368] and ssu-yu [1369] years. Altogether one hundred and eleven years elapsed. These passages would suggest that Ta-tu was called Na-cha city because its gates were designed to symbolize the body of the supernatural deity known as Na-cha. What was the origin of this bizarre legend? Who was Na-cha and what sort of extraordinary power did he command that compelled Liu Ping-chung to construct Ta-tu's gates in his likeness? And what is the impact of this legend on the folk traditions surrounding the building of Peking later? The principal character in this legend, Na-cha (later also transcribed as No-cha), originally Nata in Sanskrit, was a child deity, the third son of Vaisravana, one of the four "Heavenly Kings" who in the Buddhist tradition was guardian of the north. In the sutras of Tantric Buddhism introduced to China during the early T'ang dynasty, Na-cha is endowed with an extraordinary physique and divine power, capable of transforming himself at will and performing miraculous feats. He is credited with assisting his father in defending the city of An-hsi in western China against foreign invasion. Furthermore, his superior power and magical charms were effective in exorcizing the wicked demons and subduing the heavenly dragon who caused droughts. By the late T'ang and early Sung, the popular imagination had incorporated Na-cha into the mythological genealogy of the early T'ang general Li Ching (571-649), who had by this time been transformed into a Taoist guardian god. Grafted onto this historical figure were some of the most fanciful legends associated with King Vaisravana. What emerged was a mythologized hero known as Pagoda-bearing Heavenly King Li Ching. Na-cha, now a prince and the third son of the Heavenly King, is described as being sixty feet tall, having three heads, six arms (later eight arms) and two feet. In the course of time, many miraculous episodes of Buddhist and Taoist provenance were attributed to Na-cha. One of the most dramatic and one which is directly related to the legends surrounding Ta-tu concerns Na-cha's feuds with the dragon genii.… [ABSTRACT FROM AUTHOR]