The Legion of the Just Ruler (Dutch: Legioen van de Rechtvaardige Vorst, Indonesian: Angkatan Perang Ratu Adil; APRA) or the Legion of Ratu Adil was a pro-Dutch militia and private army established in the aftermath of the Indonesian National Revolution.
[1] The militia's name was derived from a passage from the medieval Book of Prophecies of Joyo Boyo which prophesied the coming of a Just Ruler (Ratu Adil) who would be of Turkish descent and come to save the people of Java and establish universal peace and justice.
[3] APRA was recruited from several anti-Republican factions including former Republican guerrillas, Darul Islam fighters, Ambonese, Malays, Minahasans, demobilised KNIL, Special Forces Regiment and Royal Netherlands Army personnel.
[5] Unhappy with the growing influence of Sukarno's government, Westerling conspired with the federalist Sultan of Pontianak Hamid II to launch a coup in January 1950.
Westerling had planned to overthrow the RUSI Cabinet and assassinate several prominent Republican figures including the Defense Minister Sultan Hamengkubuwono IX and Secretary-General Ali Sadikin.