sparking rebellions on their desert frontiers. The Lakhmids also revolted against the Persian king Khusrau II. Nu'man III (son of Al-Monder IV), the first Christian Lakhmid king, was deposed and killed by Khusrau II in 602, because of his attempt to throw off Persian suzerainty. After Khusrau's assassination in 628, the Persian Empire fractured and the Lakhmids were effectively semi-independent. It is now widely believed that the annexation of the Lakhmid kingdom was one of the main factors behind the fall of the Sasanian Empire and the subsequent Islamic conquest of Persia, as the Lakhmids agreed to act as spies for the Muslims after being defeated in the Battle of Hira by Khalid ibn al-Walid. Byzantine–Sassanid War (602–628) The Persian ruler Khosrau II (Parviz) defeated a dangerous rebellion within his own empire, Bahram Chobin's rebellion. He then turned his focus to his traditional Byzantine enemies, leading to the Byzantine-Sassanid War of 602–628. For a few years, he succeeded. From 612 to 622, he extended the Persian borders almost to the same extent that they were under the Achaemenid dynasty (550–330 BC), capturing Western states as far as Egypt, Palestine (the conquest of the latter being assisted by a Jewish army), and more. The Byzantines regrouped and pushed back in 622 under Heraclius. Khosrau was defeated at the Battle of Nineveh in 627, and the Byzantines recaptured all of Syria and penetrated far into the Persian provinces of Mesopotamia. In 629, Khosrau's general Shahrbaraz agreed to peace, and the border between the two empires was once again the same as it had been in 602. Plague of Sheroe The Plague of Sheroe (627–628) was one of several epidemics that occurred in or close to Iran within two centuries after the first epidemic was brought by the Sasanian armies from its campaigns in Constantinople, Syria, and Armenia. It contributed to the fall of the Sasanian Empire. Execution of Khosrau II Khosrau II was executed in 628 and, as a result, there were numerous claimants to the throne; from 628 to 632 there were ten kings and queens of Persia. The last, Yazdegerd III, was a grandson of Khosrau II and was said to be a mere child aged 8 years. Muhammad's Letter After the Treaty of Hudaybiyyah in 628, Islamic tradition holds that Muhammad sent many letters to the princes, kings, and chiefs of the various tribes and kingdoms of the time,