The Isle of Man, also known simply as Mann, is a self-governing Crown dependency in the Irish Sea between the islands of Great Britain and Ireland. The head of state is Queen Elizabeth II, who holds the title of Lord of Mann. The Lord of Mann is represented by a Lieutenant Governor. Foreign relations and defence are the responsibility of the British Government.The island has been inhabited since before 6500 BC. Gaelic cultural influence began in the 5th century and the Manx language, a branch of the Gaelic languages, emerged. In 627, Edwin of Northumbria conquered the Isle of Man along with most of Mercia. In the 9th century, Norsemen established the Kingdom of the Isles. Magnus III, King of Norway, was also known as King of Mann and the Isles between 1099 and 1103.In 1266, the island became part of Scotland under the Treaty of Perth, after being ruled by Norway. After a period of alternating rule by the kings of Scotland and England, the island came under the feudal lordship of the English Crown in 1399. The lordship revested into the British Crown in 1765, but the island never became part of the Kingdom of Great Britain or its successor the United Kingdom: it retained its status as an internally self-governing Crown dependency.