It's not that complicated, the land in question has been owned by a conquering empire for the better part of two millenia. After WWII and emipres falling out of favor, splitting it up was decided. The locals didn't like the jews getting a country and attacked, they lost. They mobilized for round two, and Israel hit first and won again. Since then Israel started giving back land it seized to the respective countries, in exchange for not attacking again. The region has been at an uneasy truce for 50ish years other than Palestine launching terrorist attacks every few years.