The line separating the British and French spheres of interest in the area was first defined in the 1916 Sykes-Picot agreement. Britain's military occupied the region during the First World War, and in 1920 the French army invaded Syria. On 8 August 1920, during the Transjordan interregnum period, the French confirmed to the British that they would respect the Sykes-Picot line, and not move any military forces south.