Ngāi Tahu originated in the Gisborne District of the North Island, along with Ngāti Porou and Ngāti Kahungunu, who all intermarried amongst the local Ngāti Ira. Over time, all but Ngāti Porou would migrate away from the district. Several were already occupying the South Island prior to Ngāi Tahu's arrival, with Kāti Māmoe only having arrived about a century earlier from the Hastings District, and already having conquered Waitaha, who themselves were a collection of ancient groups. Other that Ngāi Tahu encountered while migrating through the South Island were Ngāi Tara, Rangitāne, Ngāti Tūmatakōkiri, and Ngāti Wairangi – all of which also migrated from the North Island at varying times. During the 1800s mass groups of Europeans, particularly the British, began to migrate to New Zealand. After European arrival, Ngāti Toa (allied with Ngāti Tama) and Ngāti Rārua invaded Ngāi Tahu's territory with muskets. Inevitably the Europeans intermingled with native populations, and today, most families who descend from Ngāi Tahu also have Ngāti Māmoe and British ancestry.