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. While the Chief of Defence (CDF) commands the Australian Defence Force (ADF), the Army is commanded by the Chief of Army (CA). The CA is therefore subordinate to the CDF, but is also directly responsible to the Minister for Defence. 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.