[11][12] Between 1836 and 1839 Fairburn began moves to establish a mission station at Maraetai while attempting to purchase a vast tract of land from various iwi of Auckland.
Brokered as "an act of Christian peacemaking" between warring tribes on the Auckland isthmus, Fairburn obtained "signatures" to the deed of purchase from over 30 rangatira (chiefs); few, if any of whom could read or write.
With the agreement of local Maori at a meeting at Puneke on the Tamaki River on 22 January 1836, he purchased the entire Bucklands Beach, Howick and Pakuranga area of 40,000 acres (160 km2).
The Treaty of Waitangi was signed at Karaka Bay on the Tamaki River opposite Big Bucklands Beach in 1840 by Capt Hobson and Ngati Paoa.
When the purchase came under scrutiny from the CMS, in 1837 Fairburn signed a deed promising to return one third of the land to the original inhabitants (a transaction which never took place), and unsuccessfully attempted to offer another third to the Church.
Following the protests of Hori Te Whetuki on behalf of Ngāi Tai, in 1854 the Commission granted a "Native Reservation" of just over 6,000 acres (24 km2) at Duders Beach (Umupuia) to "the chiefs of the Ngatitai" and paid them £500 compensation, on the condition that they sign an agreement to vacate all other lands within the original purchase boundaries, and order all other iwi to do the same.