The Australian Army is Australia's military land force. It is part of the Australian Defence Force (ADF) along with the Royal Australian Navy and the Royal Australian Air Force. Although Australian soldiers have been involved in a number of minor and major conflicts throughout its history, only in World War II has Australian territory come under direct attack.
The Australian Army was mobilised in 1938 when World War II began, but didn't see any major action until January 1941, when Japan opened up the war in the Pacific. The army was a part of the defence of the Dutch East Indies, when the Japanese invaded the islands. However, they were unable to stop the Japanese from conquering a large swath of territory through the islands.