British and Turkish officials met in 1924 but were unable to determine a mutually satisfactory border, and the matter was referred to the League of Nations.[1] In October 1925 the League proposed a border (the ‘Brussels line’) that was essentially the same as that of the northern limits of the old Mosul Vilayet.[3][6] After further deliberations, the League formally recommend in July 1925 that the Brussels line be utilised, a view endorsed by the Permanent Court of International Justice at the Hague in November 1925.[3] On 5 June 1926 Britain and Turkey signed the Treaty of Ankara, by which both states recognised the Brussels line (with some minor modifications) as the frontier.[3][7] The border was then demarcated on the ground in 1927.[3]