The origins of the cathedral date back to the plans of the Canterbury Association, which aimed to build a city around a central cathedral and college in the Canterbury region, based on the English model of Christ Church Cathedral, Oxford. In the original survey of central Christchurch (known as the Black Map), undertaken in 1850, it was envisaged for the college and cathedral to be built in Cathedral Square. The area set aside for the college was found to be insufficient, and Henry Sewell suggested in June 1853 to move it to land reserved for the Christchurch Botanic Gardens. This transaction was formalised through "The Cathedral Square Ordinance 1858" passed by the Canterbury Provincial Council in October 1858. The ordinance allowed for Colombo Street to go through the middle of Cathedral Square at a legal width of with the cathedral to the west.