The four Lokapalas or "Guardian Kings" of the four Cardinal Directions are stationed halfway up the cosmic mountain, Mount Sumeru, from where they protect the four corners of the world. Their presence in the Buddha’s entourage is explained by their role as protectors of Buddhist Law. In Chinese, they manifest as Tian Wang (Heavenly Kings) who are dressed in full parade armor, and Lishi (Strong Men) who are depicted bare-chested and wearing a short tunic.
During the beginning of the Tang dynasty (618-907AD), tomb furnishings contained a pair of military officials and a pair of civil officials. By the middle of the 7th century, the military officials were gradually replaced by images of Tian Wang possessing foreign facial features. Originally, these stood with feet together, but later on, they were sculpted in the S-shaped stance seen in Buddhist carvings of the latter 7th century, their weight on one leg and one hand on hip while the other hand was raised in a fist. These Tian Wang were placed along with the two Guardian Beasts inside the entrance to the tomb and were charged with its protection. One of the pair stood on top of a vanquished demon or "Earth Spirit" while the other stood on an animal, usually an ox. Particularly grand examples would be shown astride two or even three Earth Spirits, the whole ensemble set upon a rockwork base representing Mount Sumeru. The statues are generally shown wearing full parade armor, and a helmet crested by a fantastic bird with wings outspread and plume-shaped tail, said to represent martial valor. This armor is an accurate depiction of military costume of the period, with the famous reflective breastplates said to blind the enemy in battle, and monster masks over the epaulettes and abdomen. As we approach the High period of the Tang dynasty, the figures become ever more exaggerated in pose and ferocity of expression, while their lines become progressively more baroque with the tunic and outer sleeves depicted in mid-flight, caught in the wind. As with all Tang tomb sculptures, they can be found in the painted and gilt versions in grey, red, or cream terracotta, or in the famous Sancai (tri-color glaze) ware, ranging in size from 30cm to well over a meter in height. The head, torso, arms, and legs of each figure are made separately in two-part moulds before being joined using strips of clay. As sumptuary laws were in place regarding tomb appointments, the largest Sancai pieces are generally indicative of imperial burials, although this is not always the case. Very rare freestanding Lokapalas of marble have also been discovered.
Wonderful depictions of martial valor, these Lokapalas are evidence of the pervasive influence of Buddhism in Tang society.