Short answers, pulled from the story.
The office of Admiral of England emerged around 1400 to manage maritime affairs. King Henry VIII established the Council of the Marine in 1546 to handle administrative duties for the naval service.
Sir James Graham abolished the Navy Board in 1832. This dual system had persisted since 1546 but suffered from inefficiency and corruption due to limitations of the era.
King Charles I put the office of Lord High Admiral into commission in 1628. Control passed to a committee called the Board of Admiralty composed of Naval Lords and Civil Lords.
After 1806, the First Lord of the Admiralty was always a civilian while the professional head came to be known as the First Sea Lord. The First Sea Lord acted as Chief Naval Adviser on the Board of Admiralty to the First Lord.
In 1964, the Admiralty along with the War Office and Air Ministry were abolished as separate departments. They were placed under one single new Ministry of Defence which contains the Admiralty Board and Navy Board.
Queen Elizabeth II awarded the title to Prince Philip Duke of Edinburgh on his 90th birthday in 2011. It remained with him until his death in 2021.