Dutch conquest exerted colonial control across the archipelago in the 19th century, establishing a unitary administration. The borders of present-day Indonesia were formed through colonial expansion finalised in the 20th century. After the occupation by the Japanese Empire during World War II ended in 1945, nationalist leaders on Java unilaterally declared Indonesian independence. Early organised indigenous resistance came from the South Moluccas with support and aid from the Dutch government and military. The South Moluccan rebels initially clung on to an early post-colonial treaty prescribing a federal form of statehood. When that treaty, agreed between the Dutch government and the Indonesian government in December 1949, was broken, they unilaterally declared a fully independent "Republic of South Maluku" (RMS) in April 1950. The South Moluccan leaders based their decision on the treaty, which stipulated autonomy for each of the states of the federation.