Hello, my name is Charles.  British diplomacy had been instrumental in starting the Arab Revolt that helped destroy the Ottomans, so they were given most of the Middle East to do with as they pleased after The War ended.  But they had made three conflicting promises.  First, they promised individual families lordship over many lands.  Second, they promised to support a united Arab state.  And finally, they promised a return of the Jews to their homeland.  And so began over a century of warfare.