In 1864, he joined a botany expedition to the South Sea Islands and was wrecked off the coast of Samoa, where he was stranded for eighteen months, before being rescued and brought to Fiji.In June 1871, Thurston, then Britain's honorary consul, forged a "marriage of convenience" between the Bauan chief Seru Epenisa Cakobau and the British settlers.He persuaded the Fijian chiefs to surrender the independence of their fiefdoms and accept a constitutional monarchy with Cakobau as acclaimed King, but with real power in the hands of a cabinet and legislature dominated by settlers.The murder of Bishop John Patteson of the Melanesian Mission at Nukapu in the Reef Islands had provoked public outrage, which was compounded by the massacre by crew members of more than 150 Fijians on board the brig Carl.The negotiations were concluded with Thurston himself acting as Premier, from 23 March to 10 October 1874, when Cakobau and his fellow-chiefs formally ceded the archipelago to the United Kingdom.