James Cook, the British explorer, navigator, and cartographer, made a pivotal landing on Possession Island as part of his first voyage in the Pacific. After navigating through the waters of the east coast of Australia aboard the HMS Endeavour, Cook anchored near the island on August 22, 1770, during which he performed a solemn ceremony. In this ritual, Cook planted a British flag on the island and formally claimed the territory for Great Britain, naming it New South Wales. This event represented a pivotal moment in expanding British colonial claims in the Pacific and would later lead to significant consequences for the indigenous populations of Australia.

The decision to name and claim the eastern coastline of Australia was influenced by previous European navigations and conjectures about the potential of this vast and seemingly uncharted territory. Cook's expedition aimed to observe the transit of Venus and subsequently circumnavigate as many new lands as possible. His landing at Possession Island was marked by the symbolism of British expansion and the era of exploration during the Age of Enlightenment. This claim established the basis for future British settlements in Australia, setting the stage for the British colonization that followed, including the establishment of Sydney in 1788.

Aside from Cook's flag-planting, various personal interactions and observations chronicled by the crew highlighted the cultures and lives of the Indigenous Australians they encountered. These encounters would later be viewed through the lens of colonization and its impact on First Nations peoples, adding layers of complexity to this otherwise straightforward event of claiming territory.