In the beginning of the 7th century AD the confrontation between byzantium and persia reached its highest point. After the murder of emperor Maurikios his son Theodosios called the persian king Chosrau II. for help against the murder Phokas. Therefore persian troops overrunned the byzantine euphrat-frontier. But the persians had so much success, that Chosrau decided to occupy the byzantine provinces and defeat the old rival in the west. During 603 and 616 AD the persians occupied all the byzantine territories in asia minor, syria, palestine and egypt. On the top of their triumph persian troops brought the holy cross of jerusalem to the persian capital ctesiphon. It seemed that the old byzantine rival was finally defeated. In this situation Heraklios changed the situation. As the son of the Governor of northern africa Heraklios ascended the byzantine emperors throne in the year 610 AD. After domestic reforms he started his campains against persia in 622 AD. During his campains he became something like a new Cesar. In a long march of 1700 Kilometers he occupied the northern persian territories. Near Tigranocerta in Armenia he defeated two persian generals. Therefore he forced the persians to give up their siege of Constantinople and to withdraw behind the euphrat-frontier. 617 AD he defeated the persian troops near the old assyrian capital Ninive in a final battle. After his victory the persian nobility murdered King Chosrau II. and broght Kavadh II. up to the persian throne. He immediatly made peace with Heraklios and gave the holy cross and all persian occupations back to byzantium. 20 Years later the persian kingdom ended after their defeat in the battle of Nihavend (642 AD) against the Arabs.