In the 1750s and 1760s, longhunters from Virginia explored much of East and Middle Tennessee. Settlers from the Colony of South Carolina built Fort Loudoun on the Little Tennessee River in 1756, the first British settlement in what is now Tennessee and the westernmost British outpost to that date. Hostilities erupted between the British and the Cherokees into an armed conflict, and a siege of the fort ended with its surrender in 1760. After the end of the French and Indian War, Britain issued the Royal Proclamation of 1763, which forbade settlements west of the Appalachian Mountains in an effort to mitigate conflicts with the Natives. Migration across the mountains continued, however, and the first permanent European settlers began arriving in the northeastern part of Tennessee in the late 1760s. Most of these settlers were English, but nearly 20% of them were Scotch-Irish. They formed the Watauga Association in 1772, a semi-autonomous representative government, and three years later reorganized themselves into the Washington District to support the cause of the American Revolutionary War. The following year, after an unsuccessful petition to Virginia, North Carolina agreed to annex the Washington District to provide protection from Native American attacks.