Complex sentence: McMahon's promises are seen by Arab nationalists as a pledge of immediate Arab independence, an undertaking violated by the region's subsequent partition into British and French League of Nations mandates under the secret Sykes-Picot Agreement of May 1916.
Split into simpler sentences: McMahon's promises are seen by Arab nationalists as a pledge of immediate Arab independence. They also believe that the undertaking was violated by the region's subsequent partition into British and French League of Nations mandates under the secret Sykes-Picot Agreement of May 1916.