Complex sentence: The Chanak Crisis (or Affair) in September 1922 was the threatened attack on British and French troops stationed near Çanakkale (Chanak) to guard the Dardanelles neutral zone by Turkish troops which had recently defeated Greek forces and recaptured İzmir (Smyrna).
Split into simpler sentences: The Chanak Crisis (or Affair) in September 1922 was the threatened attack by Turkish troops on British and French troops stationed near Çanakkale (Chanak) to guard the Dardanelles neutral zone. The Turkish troops had recently defeated Greek forces and recaptured İzmir (Smyrna).