What happened
Fort-Dauphin was a French colonial settlement established in 1642 in the Anosy region of what is now Tolagnaro, Madagascar, as part of an effort by the Kingdom of France to settle the island. Between 1642 and 1674, roughly 4,000 French civilians and soldiers were sent to the fortified town. The colonists struggled with agriculture in the local environment and turned to trade, but few ships visited the colony — between 1648 and 1654 none arrived at all. The fort itself was built of hay, and houses were huts of wood and reeds, leaving the community vulnerable. The colony depended heavily on alliances with local Antanosy tribes, particularly against a rival chieftain, Dian Manangue, based near the Mandrare River to the west.
Relations between colonists and missionaries and the Antanosy population were often strained. In 1663, the French Lazarist missionary Père Étienne was killed along with colleagues after attempting to forcibly remove charms from Manangue. In response, French forces conducted a six-day campaign against Manangue's kingdom, reportedly burning 150 villages and killing around 1,000 soldiers and civilians while seizing 4,000 cattle.
Over time, colonists — who were almost entirely male — formed relationships with Antanosy women, producing mixed-race children and fostering deep social and linguistic integration with local communities. These "marriage alliances" were credited with helping keep the fort safe. However, tensions rose when the ship Dunkerquoise arrived carrying at least twelve unmarried French women who were wed to male colonists, leading Antanosy wives and concubines — fearing displacement — to end their relationships with colonists, leaving Fort-Dauphin more exposed. Antanosy chieftains, perceiving Manangue's growing power and their French allies' weakening position, allied with Manangue rather than risk being attacked themselves.
On 16 August 1674 (the article's title references an evening event on 27 August 1674, indicating some inconsistency in reported dating), Antanosy fighters attacked the poorly defended fort. At least 74 French colonists were killed, with some accounts suggesting over a hundred deaths, and hundreds more were wounded. Survivors who evaded the attackers fled aboard the ship Blanc Pignon to the island of Bourbon (now Réunion).
The massacre ended French ambitions to colonise Madagascar at that time and is described as marking the end of the first wave of French colonisation of the island. Nearly a century passed before the French returned to establish another colony, on Ile Saint-Marie, which itself was subject to attacks in 1751 and 1752. French colonial presence in Madagascar was not firmly re-established until 1897.