Editing Battle of Nineveh (627) (section)

==Prelude==
When [[Maurice (emperor)|Emperor Maurice]] was murdered by the usurper [[Phocas]], [[Khosrow II]] declared war under the pretext of avenging his benefactor's death.{{sfn|Börm|2024|p=589}} While the Persians were successful over the course of earlier stages in the war, conquering much of the Levant, Egypt, and even some of Anatolia, the resurgence of [[Heraclius]] eventually led to the Persians' downfall. Heraclius' campaigns tilted the balance towards the Romans, forcing the Persians on the defensive. Allied with the [[Pannonian Avars|Avars]], the Persians [[Siege of Constantinople (626)|attempted to take Constantinople]], but were defeated.{{sfn|Börm|2024|p=589}}

While the Siege of Constantinople was taking place, Heraclius allied with what Byzantine sources called the Khazars under [[Ziebel]], who are identified with the [[Western Turkic Khaganate]] of the [[Göktürks]] led by Tong Yabghu,<ref>{{Harvnb|Kaegi|2003|p=[https://books.google.com/books?id=tlNlFZ_7UhoC&pg=PA143 143]}}</ref> plying him with wondrous gifts and a promise of the reward of the [[porphyrogenita]] [[Eudoxia Epiphania]]. The Caucasus-based Turks responded by sending 40,000 of their men to invade the Caucasus in 626, inciting the [[Perso-Turkic war of 627–629]].{{sfn|Howard-Johnston|2016|p=124}} Joint Byzantine and Göktürk operations were focused on besieging [[Tiflis]].<ref>{{Harvnb|Kaegi|2003|p=[https://books.google.com/books?id=tlNlFZ_7UhoC&pg=PA144 144]}}</ref>