The crew of schooner Ancud, led by John Williams Wilson, takes possession of the Strait of Magellan on behalf of the Chilean government.

The schooner Ancud was the ship sent by Chile in 1843 to claim sovereignty over the Strait of Magellan and establish Fuerte Bulnes, the first Chilean settlement in the strait. It was built for the purpose in the city of San Carlos de Ancud and commanded by John Williams Wilson, a British-born Chilean captain.

John Williams Wilson (1798–1857), also known as Juan Guillermos, was an English-Chilean sailor and politician. Born in Bristol, he entered the newly founded Chilean navy in 1824 and rose to the rank of commander. He was appointed governor of Talcahuano (1849–1855). He supervised construction of Fuerte Bulnes in 1843, which the government intended for a settlement at the Strait of Magellan. Puerto Williams, founded in 1953, was named for the naval commander.

The Chilean colonization of the Strait of Magellan began in 1843 when an expedition founded Fuerte Bulnes. In 1848 the settlement of Punta Arenas was established further north in the strait and grew eventually to become the main settlement in the strait, a position it holds to this day. The Chilean settlement of the strait was crucial to establish its sovereignty claims in the area. Argentina complained diplomatically this act in 1847, as part of the East Patagonia, Tierra del Fuego and Strait of Magellan Dispute, and once the dispute was settled, formally recognised Chilean sovereignty of the strait in 1881. The Magallanes territory was made a regular Chilean province in 1928.

The Strait of Magellan, also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and the Tierra del Fuego archipelago to the south. Considered the most important natural passage between the Atlantic and Pacific oceans, the strait is approximately 570 km long and 2 km wide at its narrowest point. In 1520, the Spanish expedition of the Portuguese navigator Ferdinand Magellan, after whom the strait is named, became the first Europeans to discover it.