Editing Heraclius (section)

== Byzantine–Arab wars ==
{{Main|Arab–Byzantine wars|List of battles of Muhammad}}
[[File:Muslim-Byzantine troop movement (635-636).svg|thumb|Arab-Byzantine troop movement from September 635 to just before the event of the Battle of the Yarmouk|alt=A map with Muslim-Byzantine troop movements from September 365 to just before the event of the Battle of the Yarmouk]]
By 630, the Arabs had unified all the tribes of the [[Hijaz]], previously too divided to pose a serious military challenge to the Byzantines or the Persians. They composed one of the most powerful states in the region.{{sfn|Lewis|2002|pp=43–44}} The first conflict between the Byzantines and the Arabs was the [[Battle of Mu'tah]] in September 629. A small Arabs skirmishing force attacked the province of [[Arabia Petraea|Arabia]] in response to the Arab ambassador's death at the hands of the [[Ghassanid]] Roman governor, but were repulsed. Since the engagement was a Byzantine victory, there was no apparent reason to make changes to the military organization of the region.{{sfn|Kaegi|2003|p=231}} The Roman military wasn't accustomed to fighting Arab armies at scale, much like the Islamic forces of Hijaz who had no prior experience in their engagements against the Romans. Even the [[Strategicon of Maurice]], a [[Byzantine military manuals|manual of war]] praised for the variety of enemies it covers, does not mention warfare against [[Arabs]] at any length.{{sfn|Kaegi|2003|p=230}} The religious zeal of the Arab army, which was a recent development following the [[rise of Islam]], ultimately contributed to the latter's success in its campaigns against the Romans.{{sfn|Kaegi|2003|p=230}}

The following year, the Arabs launched an offensive into the [[Arabah]] south of [[Lake Tiberias]], taking [[al-Karak]]. Other raids penetrated into the [[Negev]], reaching as far as [[Gaza City|Gaza]].{{sfn|Kaegi|2003|p=233}} The [[Battle of Yarmouk]] in 636 resulted in a crushing defeat for the larger Byzantine army; within three years, the [[Levant]] had been lost again. Heraclius died of an illness on 11 February 641;{{efn|This is the date as given by the calculations of [[Nikephoros I of Constantinople]] (758–828): "So he died of this (disease) at the age of sixty-six after a reign of thirty years, four months, and six days".{{sfn|Nicephorus|1990|p=77}} Other authors give only the month.<ref>[[John of Nikiû]], [https://www.tertullian.org/fathers/nikiu2_chronicle.htm ''Chronicle'' CXVI:] "Heraclius fell ill with fever, and died in the thirty-first year of his reign in the month Yakâtît of the Egyptians, that is, February of the Roman months."</ref><ref>[[Theophanes Confessor]], [https://archive.org/details/chronicle-of-theophanes-the-confessor/page/474/mode/1up AM 6132]: "In the month of March, indiction 14, the emperor Herakleios died of dropsy after a reign of 30 years and 10 months."</ref> The 13th century ''[[Chronicon Altinate]]'' gives 11 January, a date that could be accepted if not for the corrupted and erroneous dates in the rest of the book.<ref>The [[Chronicon Altinate]] [http://asa.archiviostudiadriatici.it/islandora/object/libria%3A209776 107, 21–25:] "Mense ianuarii, xi die, defunctus est Eraclius imperator in infirmitate briky, hoc est disenteria".</ref>}} and most of Egypt had fallen by that time as well.{{sfn|Franzius}}