Umar ibn al-Khattab was the second, and probably the greatest, of the Moslem caliphs. He was a younger contemporary of Muhammad, and like the Prophet, was born in Mecca. The year of his birth is unknown, but was perhaps about 586.
'Umar was originally one of the most bitter opponents of Muhammad and his new religion. Rather suddenly, however, "Umar became converted to Islam, and thereafter was one of its strongest supporters. (The parallel with the conversion of St. Paul to Christianity is striking.) 'Umar became one of the closest advisors of the prophet Muhammad, and remained so throughout Muhammad's life.
In 632, Muhammad died without having named a successor. 'Umar promptly supported the candidacy of Abu Bakr, a close associate and father-in-law of the Prophet. This avoided a power struggle and enabled Abu Bakr to be generally recognized as the first caliph (i.e., as the "successor" of Muhammad). Abu Bakr was a successful leader, but he died after serving as caliph for only two years. He had, however, specifically named 'Umar (who was also a father-in-law of the Prophet) to succeed him, so once again a power struggle was avoided.
'Umar became caliph in 634, and retained power until 644, when he was assassinated in Medina by a Persian slave. On his deathbed, 'Umar named a committee of six persons to choose his successor, thereby again averting an armed struggle for power. The committee chose Othman, the third caliph, who ruled from 644 to 656.
It was during the ten years of 'Umar's caliphate that the most important conquests of the Arabs occurred. Not long after 'Umar's accession, Arab armies invaded Syria and Palestine, which at that time were part of the Byzantine Empire. At the Battle of the Yarmuk (636), the Arabs won a crushing victory over the Byzantine forces. Damascus fell the same year, and Jerusalem surrendered two years later. By 641, the Arabs had conquered all of Palestine and Syria, and were advancing into present-day Turkey. In 639, Arab armies invaded Egypt, which had also been under Byzantine rule. Within three years, the Arab conquest of Egypt was complete.
Arab attacks upon Iraq, at that time part of the Sassanid Empire of the Persians, had commenced even before Umar took office. The key Arab victory, at the battle of Qadisiya (637) occurred during Umar's reign. By 641, all of Iraq was under Arab control. Nor was that all: Arab armies invaded Persia itself, and at the battle of Nehavend (642) they decisively defeated the forces of the last Sassanid emperor. By the time Umar died, in 644, most of western Iran had been overrun. Nor had the Arab armies run out of momentum when Umar died. In the East, they fairly soon completed the conquest of Persia, while in the West they continued their push across North Africa.
Just as important as the extent of 'Umar's conquests is their permanence. Iran, though its population became converted to Islam, eventually regained its independence from Arab rule. But Syria, Iraq, and Egypt never did. Those countries became thoroughly Arabized and remain so to this day.
Umar, of course, had to devise policies for the rule of the great empire that his armies had conquered. He decided that the Arabs were to be a privileged military caste in the regions they had conquered, and that they should live in garrison cities, apart from the natives. The subject peoples were to pay tribute to their Moslem (largely Arab) conquerors, but were otherwise to be left in peace. In particular, they were not to be forcibly converted to Islam. (From the above, it is clear that the Arab conquest was more a nationalist war of conquest than a holy war, although the religious aspect was certainly not lacking.)
Umar's achievements are impressive indeed.
After Muhammad himself, he was the principal figure in the spread of Islam.
Without his rapid conquests, it is doubtful that Islam would be nearly as widespread today as it actually is.
Furthermore, most of the territory conquered during his reign has remained Arab ever since. Obviously, of course, Muhammad, who was the prime mover, should receive the bulk of the credit for those developments. But it would be a grave mistake to ignore 'Umar's contribution.
The conquests Umar made were not an automatic consequence of the inspiration provided by Muhammad. Some expansion was probably bound to occur, but not to the enormous extent that it did under Umar's brilliant leadership.
It may occasion some surprise that Umar, a figure virtually unknown in the West has been ranked higher than such famous men as Charlemagne and Julius Caesar. However, the conquests made by the Arabs under Umar, taking into account both their size and their duration, are substantially.
The views of historian Micheal Hart conforms to the great responsibilities entrusted to him by Propeht Muhammad (pbuh).
https://en.wikipedia.org/wiki/Umar
http://arankingofthe100.blogspot.com/2011/09/michael-h-hart.html
https://Quran1Book.blogspot.com
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