The War Office was a department of the British government responsible for the administration of the British Army. Established in the late 17th century, it played a crucial role in military planning, logistics, and personnel management. The War Office oversaw military operations and coordinated with other government departments during times of conflict. In 1964, the War Office was merged with the Admiralty and the Air Ministry to form the Ministry of Defence. This change aimed to streamline military administration and improve coordination among the armed forces. The War Office's historical significance remains as a key institution in the development of modern military governance in the UK.