The Royal Navy (RN) is the United Kingdom's principal naval warfare force. Tracing its origins to the 16th century, it is the oldest of the armed services and is known as the Senior Service. From the end of the 17th century until well into the 20th century it was the most powerful navy in the world, playing a key part in establishing the British Empire as the dominant world power. Due to this historical prominence, it is usual – even among non-Britons – to refer to it as "The Royal Navy" without qualification.