(This article is about the United Kingdom's navy. For other uses, see Royal Navy (disambiguation) and Senior Service (disambiguation).) The Royal Navy (RN) is the United Kingdom's principal naval warfare force. Naval forces were first used by Alfred the Great in the 9th century, and from the early 14th century England's navy was engaged in maritime warfare. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is known as the Senior Service.