Admiralty
It evolved from *Admiralty Navy War Council, (1909–1912) which in turn became the Admiralty War Staff, (1912–1917) before finally becoming the Admiralty Naval Staff in 1917. It was the former senior command, operational planning, policy and strategy department within the British Admiralty. It was established in 1917 and existed until 1964 when the department of the Admiralty was abolished, and the staff departments function continued within the Navy Department of the Ministry of Defence until 1971 when its functions became part of the new Naval Staff, Navy Department of the Ministry of Defence.
Marine Department (Royal Navy)
The Marine Department originally called the Marine Office was established in 1755 as a consequence of the creation of the Corps of the Royal Marines. under Admiralty control. The department was a civilian civilian secretariat, who's role was to correspond and coordinate the administrative and logistical concerns of the three Marine divisions with the Admiralty that were located at Chatham, Plymouth, Portsmouth and Woolwich whose colonels were the most senior Marine officers. Subsequently a Colonel-Commandant at Marine Headquarters in London was established as the senior officer of the Corps, the forerunner of the modern Adjutant-General of the Royal Marines. The department existed until 1809 when its functions were assumed by the Marine Pay Department.. The department was managed by the First Secretary to the Admiralty who was supported by the Second Secretary to the Admiralty who were both given the additional titles of Secretary then later First Secretary of the Marine; and Deputy Secretary later Second Secretary of the Marine.