at Auschwitz concentration camp in order to identify the bodies of registered prisoners in the concentration camps. During registration, guards would pierce the outlines of the serial-number digits onto the prisoners' arms. Of the Nazi concentration camps, only Auschwitz put tattoos on inmates. The tattoo was the prisoner's camp number, sometimes with a special symbol added: some Jews had a triangle, and Romani had the letter "Z" (from German Zigeuner for "Gypsy"). In May 1944, Jewish men received the letters "A" or "B" to indicate a particular series of numbers. As early as the Zhou, Chinese authorities would employ facial tattoos as a punishment for certain crimes or to mark prisoners or slaves. During the Roman Empire, gladiators and slaves were tattooed: exported slaves were tattooed with the words "tax paid", and it was a common practice to tattoo "fugitive" (denoted by the letters "FUG") on the foreheads of runaway slaves. Owing to the Biblical strictures against the practice, Emperor Constantine I banned tattooing the face around AD 330, and the Second Council of Nicaea banned all body markings as a pagan practice in AD 787. Cultural identification In the period of early contact between the Māori and Europeans, the Māori people hunted and decapitated each other for their moko tattoos, which they traded for European items including axes and firearms. Moko tattoos were facial designs worn to indicate lineage, social position, and status within the tribe. The tattoo art was a sacred marker of identity among the Māori and also referred to as a vehicle for storing one's tapu, or spiritual being, in the afterlife. Postmortem identification Tattoos are sometimes used by forensic pathologists to help them identify burned, putrefied, or mutilated bodies. As tattoo pigment lies encapsulated deep in the skin, tattoos are not easily destroyed even when the skin is burned. Identification of animals Pets, show animals, thoroughbred horses, and livestock are sometimes tattooed with animal identification marks. Ear tattoos are a method of identification for beef cattle. Tattooing with a 'slap mark' on the shoulder or on the ear is the standard identification method in commercial pig farming. Branding is used for similar reasons and is often performed without anesthesia, but is different from tattooing as no ink or dye is inserted during the process, the mark instead being caused by permanent scarring of the skin. Pet dogs and cats are sometimes tattooed with a serial