United Nations Command is the multinational military force established under UN authority to support the Republic of Korea during and after the Korean War. It was the first international unified command established by the UN Security Council and the first attempt at collective security under the UN System after the UN Charter was signed. It was the first time that the Security Council authorized the use of force under Chapter VII of the Charter. UN Security Council Resolutions 83 and 84 provided the international legal authority for Member States to use military force to "restore peace on the Korean Peninsula" and designated the United States as the leader of the UN forces, with General Douglas MacArthur appointed Supreme Commander of the UNC.