During the following enslavement the Māori invaders forbade the speaking of the Moriori language. They forced Moriori to desecrate their sacred sites by urinating and defecating on them. Moriori were forbidden to marry Moriori or Māori, or to have children with each other. This was different from the customary form of slavery practiced on mainland New Zealand. However, many Moriori women had children by their Māori masters. A small number of Moriori women eventually married either Māori or European men. Some were taken from the Chathams and never returned. In 1842 a small party of Māori and their Moriori slaves migrated to the subantarctic Auckland Islands, surviving for some 20 years on sealing and flax growing. Only 101 Moriori out of a population of about 2,000 were left alive by 1862, making the Moriori Genocide one of the deadliest in history.