Sacrifice of certain animals has long been part of Confucian observances, both of the Master’s birthday and of certain types of ancestor memorial. Two kinds of ritual sacrifice have also been historically associated with CIT. The Feng (high altar mound) and Shan (level ground) sacrifices were those offered to Heaven and Earth, respectively. Some emperors used the public performance of these rituals as a way of declaring and expressing gratitude for their possession of the Mandate of Heaven. History records that a number of emperors, even down to the last dynasty, engaged in the sacrifices atop or at the foot of sacred mountains. Animals sacrificed ritually most commonly included sheep and pigs, but occasionally wild game animals like deer were also sacrificed. Larger and more expensive ceremonies might feature oxen splayed across a rack after slaughtering, or the burnt offering of a whole young red bull—red is the color of Yang, the energy needed to return warmth to the earth so that spring will renew all living things. In the Temple of Heaven complex, for example, a large slaughterhouse and “spirit kitchen” accommodated extensive sacrificial needs. Eighty butchers and two hundred eighty cooks processed vast quantities of material. A year’s worth of sacrifices, according to one record, included nearly a thousand pigs, over eight hundred sheep, over two hundred each of deer, cows, and rabbits, and over a hundred goats.