Marc Joseph Marion du Fresne was baptised on 22 May 1724 at St Malo, Brittany, France. His exact date of birth is unknown. He was the son of Marie Séraphique Le Fer and her husband, Julien Marion du Fresne, a merchant. In 1735, while still very young, Marion du Fresne joined the French India Company ship Duc de Bourgogne as honorary sub-lieutenant. He commanded various privateers based at St Malo during the War of the Austrian Succession, attaining the rank of temporary captain in 1745. After Culloden he sailed to Scotland and brought back to France Prince Charles Edward. He then served in the French royal navy and was taken prisoner by the English in May 1747.
After the war Marion du Fresne served in various French India Company ships, sailing to the Indian Ocean and to China. Back in France during the Seven Years' War he was consulted on a proposed French landing in Scotland. He spent two years in various naval operations, outwitting the British who were blockading the coast of Brittany. In 1759 he was promoted to fireship captain, and in 1761 he was made a Knight of St Louis. He then returned to trading in eastern waters, carried out hydrographic surveys around Mauritius and acted for a time as harbourmaster in Port Louis, where he settled. From there he traded in the Seychelles and India, and speculated in land.
The liquidation of the French India Company caused him some financial difficulties and he welcomed the opportunity in 1771 of setting off for the Pacific on a voyage of trade and exploration sponsored by the French authorities. He was provided with two naval vessels: the Mascarin of 22 guns and the Marquis de Castries of 16 guns. The first object of the expedition was to return the Tahitian Ahu-toru to his home. Ahu-toru had been taken to France by Louis-Antoine de Bougainville in 1768, and after being lionised in Paris, had been sent to Mauritius in the hope that he would find a passage back to Tahiti.
The ships sailed from Port Louis on 18 October 1771, going to the nearby islands of Bourbon and Madagascar to take on supplies and also to escape an epidemic of smallpox ravaging Mauritius. Ahu-toru died from the disease. Since it was no longer necessary to sail to Tahiti, Marion du Fresne endeavoured to recoup some of the costs of the expedition by heading for Cape Town to start a search for the southern continent in high latitudes. He discovered various islands in the south Indian Ocean: Marion Island, Prince Edward Island and the Crozets. After spending several days in Tasmania he set sail for New Zealand.
Marion du Fresne sighted Mt Taranaki on 25 March 1772, naming it Pic Mascarin. He then sailed north and on 15 April landed at Spirits Bay. A gale two days later caused severe damage to the ships and the loss of several anchors. Marion du Fresne then proceeded south-east and on 4 May reached the Bay of Islands. His ships anchored first south of Ōkahu Island and later off Moturua Island.
The next five weeks were spent exploring the Bay and repairing the ships. This leisurely stay enabled Marion du Fresne and his men to visit quite distant pa, to trade and to fish. They set up camps ashore, one for the sick on Moturua, one on the mainland as a store and centre of communication, and a third inland for cutting masts and spars. Communication with the Māori people was made possible by the use of an extensive Tahitian vocabulary prepared by Bougainville and Ahu-toru. There were occasional minor thefts, but nothing occurred to mar friendly relations and on 8 June Marion du Fresne was welcomed at a special ceremony. But four or five days later, on 12 or 13 June 1772, he was attacked and killed along with other members of a fishing party which had gone ashore. A second party was attacked the next day. In all, 25 officers and men lost their lives.
Julien Crozet, the second in command, and Ambroise-Bernard-Marie le Jar du Clesmeur, the captain of the Marquis de Castries, set about securing the ships, abandoning the camps and fighting off minor raids. The ships could not leave promptly since repairs were incomplete and the timber at the bush camp could not be brought out. Crozet and du Clesmeur decided to clear the area by a counter-attack which soon turned into violent reprisals, causing an estimated 250 Māori casualties. The French eventually sailed on 13 July for the central Pacific and the Philippines.
The reasons for the killing of Marion du Fresne and his men may never be known. The local Ngare Raumati were over-run by the Ngāpuhi a few years later and no clear account survived. It is likely that the French transgressed in some way, possibly on the fatal day, or more probably on a number of earlier occasions, until it was felt that they had gone too far. Probably a visit of five weeks with no clear signs of departure created serious economic and cultural strains. Had the Māori feared a permanent French settlement, internal politics would have exacerbated the situation.
The stay, remarkable for its length and the closeness of the contact established between the visitors and the indigenous people, produced many records of early Māori life. Marion du Fresne's own journals have not been found, but there are extensive notes in the logs and records of Crozet, du Clesmeur, Jean Roux and others, and charts and drawings, including detailed plans of a pā.
Marion du Fresne was a Māoriphile who shared Jean-Jacques Rousseau's beliefs about the 'noble savage'. The events of July 1772, however, strengthened the view in France that New Zealand was inhabited by dangerous natives and did not warrant an attempt at colonisation.