Yazid ibn Abi Sufyan

Yazid ibn Abi Sufyan () was a leading Arab general at the time of the Islamic conquest of Syria, and the elder brother of Muawiya ibn Abi Sufyan (who later became a caliph and the founder of Umayyad dynasty).
Biography.
Yazid ibn Abi Sufyan was the son of Abu Sufyan ibn Harb and Zaynab bint Nawfal, hence a paternal half-brother of Muawiya I. He was born after Umar, the second Rashidun caliph and the overall second caliph of Islam, but before Muawiya I, his paternal brother. Umar was his distant relative through his marriage to Ali's daughter, Umm Kulthoom, and his daughter, Hafsa's marriage to Muhammad. Both Muhammad and Ali were cousins and Ali eventually married his daughter, Fatima, becoming his son-in-law. Abu Bakr, Umar, Uthman and Ali were all Rashidun caliphs and relatives of Muhammad (even in-law), becoming them relatives of Abu Sufyan, Yazid and Muawiya I. They were also the Caliphs before Muawiya I and his son, Yazid ibn Muawiya.
Campaign into Syria.
Yazid was one of four Muslim generals who were sent by Caliph Abu Bakr to invade Roman Syria in 634 AD. He became governor of Damascus after the Conquest of Damascus in 634 AD. He commanded the Muslim army's left wing at the Battle of Yarmouk. After the death of Abu Ubaidah ibn al-Jarrah in 639 AD from plague, Mu'adh ibn Jabal was made governor of Syria and after his death, also from the plague, Yazid was made governor by Caliph Umar, but he too died in a plague in 640 AD.
According to al-Waqidi, the first Muslim historian on the events, Yazid was the first commander with 1000 horsemen sent to Syria and Palestine by Abu Bakr. Rabi‘ah bin Amir of the Amir tribe was sent along with another 1000 horsemen and was placed under Yazid's command. In the meantime, Christian Arabs living in Medina gave intelligence to the Roman emperor, Heraclius, about the impending invasion. Heraclius sent a force of 8000 cavalry units, commanded by Batlic; Sergius, his brother; Luke, son of Samuel and chief of police; and Salya, governor of Gaza and Ashkelon.
As soon as Yazid reached the desert on the outskirts of Medina, their Arab race horses picked up speed. Rabi‘ah bin Amir asked: "Why are you doing this?", Yazid ibn Abi Sufyan replied: "More bands will be sent after me". Yazid ibn Abi Sufyan then crossed into the Negev near Gaza. Sergius was sent by the Romans to show them the brute force of Roman might.
Yazid ordered Rabi‘ah bin Amir to hide in an ambush with 1000 horsemen while he himself led 1000 horsemen to face the Romans and draw them into rows. When the Romans arrived, on seeing Yazid's small force they thought this to be the entire Arab force and attacked. Rabi‘ah then ambushed Sergius' troops on the afternoon of 4 February, some 12 miles east of Gaza. Tom Holland says that "the specific time and date is derived from a notice in a Syrian chronicle written sometime around the year 640 and which in turn seems to draw on a near-contemporary record". Al-Waqidi's account matches the Roman account of the events.. The result was an utter debacle for the Romans at the Battle of Tabuk. The Romans were used to paying off the Arab tribes that lived in Syria. So Sergius asked Rabiʿah: "Come and work for us. We will pay you to attack the Persians." But things had changed in Arabia and these people were different. Rabiʿah refused.
Heraclius was furious and then organized an army of 100,000 men. According to Al-Imam al-Waqidi, the first Muslim historian on the events, Abu Bakr then appointed Muawiyah's friend 'Amr ibn al-'As to lead the next band of 9000 men and they left for Palestine. Tom Holland in his book "The shadow of the sword, The Battle for Global Empire and the End of the Ancient World" writes: "With intense cunning the Arabs then launched a pincer movement against the Roman army. The second band then crossed the eastern frontier even as first one was in Gaza". When they arrived in Palestine Amr's say his friend Amir bin Adi returning from Palestine after visiting his family. Amir bin Adi told him there was a Roman Army 100,000 strong behind him that had been sent to confront him. 'Amr ibn al-'As then sent Abdullah ibn Umar with 1000 horsemen to gather intelligence on the Roman Army. They saw a Roman Reconnaissance of, according to Abdullah ibn Umar, 10,000 horsemen and took them on. Then returned to 'Amr ibn al-'As. Then 'Amr ibn al-'As with Abdullah ibn Umar took on another group.
Abu Bakr then sent Abu Ubaydah towards Syria, slowly encircling the Roman armies. As news of the huge army Heraclius was assembling reached Abu Bakr, Abu Bakr then sent a letter to Khalid ibn al-Walid who was close to defeating the Persian Empire at Qadisiyah. Emperor Heraclius had sent all his available garrisoned troops into Syria, towards Ajnadayn, to hold the Muslim troops at the Syria-Arabia border region. The possible route of any Muslim reinforcement was expected to be the conventional Syria-Arabia road in the south, but Khalid, who was then in Iraq, took the most unexpected route: marching through the waterless Syrian desert, to the surprise of the Byzantines, he appeared in northern Syria. Catching the Byzantines off guard, he quickly captured several towns, virtually cutting off the communications of the Byzantine army at Ajnadayn with its high command at Emesa, where emperor Heraclius himself resided.