Shooting of a Māori by an English sailor results in the opening of the Wanganui Campaign of the New Zealand Wars.

Māori are the indigenous Polynesian people of mainland New Zealand. Māori originated with settlers from East Polynesia, who arrived in New Zealand in several waves of canoe voyages between roughly 1320 and 1350. Over several centuries in isolation, these settlers developed a distinct culture, whose language, mythology, crafts, and performing arts evolved independently from those of other eastern Polynesian cultures. Some early Māori moved to the Chatham Islands, where their descendants became New Zealand's other indigenous Polynesian ethnic group, the Moriori.

The Whanganui campaign was a brief round of hostilities in the North Island of New Zealand as indigenous Māori fought British settlers and military forces in 1847. The campaign, which included a siege of the fledgling Whanganui settlement, was among the earliest of the 19th century New Zealand Wars that were fought over issues of land and sovereignty.

The New Zealand Wars took place from 1845 to 1872 between the New Zealand colonial government and allied Māori on one side, and Māori and Māori-allied settlers on the other. Though the wars were initially localised conflicts triggered by tensions over disputed land purchases, they escalated dramatically from 1860 as the government became convinced it was facing united Māori resistance to further land sales and a refusal to acknowledge Crown sovereignty. The colonial government summoned thousands of British troops to mount major campaigns to overpower the Kīngitanga movement and also conquest of farming and residential land for British settlers. Later campaigns were aimed at quashing the Pai Mārire religious and political movement, which was strongly opposed to the conquest of Māori land and eager to strengthen Māori identity. Māori religious movements that promoted pan-Māori identity played a major role in the Wars.