Political map of Australia, New Zealand & the Southwest Pacific 15 March 1893 (Partition of the Solomon Islands): When Germany annexed northeast New Guinea in 1884 (German New Guinea), its claim included the northern Solomon Islands. The following decade the British annexed the southern Solomon Islands (British Solomon Islands), persuading the Germans to cede their claim to all of the northern Solomons except for Bougainville in 1899 (Tripartite Convention (1899)).