On 15 January 1765, Commodore John Byron in HMS Dolphin anchored in a vast natural harbor on Saunders Island, naming it Port Egmont in honor of the First Lord of the Admiralty, and formally took possession of the islands for King George III of Great Britain.

Spanish colonial authorities in Buenos Aires invoked the 1493 Papal Bull Inter Caetera to claim an absolute Spanish monopoly across the entire southern hemisphere. However, in the Law of Nations (Hugo Grotius and Emer de Vattel), papal grants held zero legal validity against sovereign Protestant crowns; territorial title required actual discovery, physical occupation, and effective settlement.

Great Britain planted settlements, established gardens, and built blockhouses at Port Egmont, cementing a legal title 45 years before the May Revolution of 1810 created the precursor to the Argentine state.