Umar ibn al Khattab (586-644), known as Umar I, was the Arab Caliph (reigned 634-644). From the Hashim tribe of the Gulai tribe where Muhammad resided, he was one of the important figures who followed Muhammad in the early days and was also his most loyal follower. Omar possessed an iron willed spirit, and together with the prophets, he experienced important tests such as "running away from Medina" and "trench warfare", often reversing the situation at critical moments of the battle. He and the first Caliph Abu Berkel are known as the "two great assistants of the prophets.".

Fu Bi
Omar I, whose full name is Omar ibn Hatab, came from the Hashim family of the Gulai tribe where Muhammad resided. He was one of the important figures who followed Muhammad in the early days and was also his most loyal companion and comrade in arms. Omar possesses a steel like will, and together with the prophets, he has experienced important tests such as "running away from Medina" and "trench warfare", often reversing the situation at critical moments in battles. He was one of the "two great prophets" along with the first Caliph Abu Berk. [1]
succession
After the death of the Prophet in 632 AD, with the support of Omar, Abu Berk, who belonged to the Hashemite family, defeated the challenges of the "Ashikaga," "Ali," and "Umayyad," and successfully became the first Caliph (meaning the successor of the Prophet). Under the cultivation of Abu Bakr, Omar also successfully became the second leading figure in the upper echelons of Muslim community organizations, and was elected as the second caliph after Abu Bakr's death in 634 AD. These two smooth transitions have maintained the unity of the Arabs and enabled the Arab Empire Building to take shape, laying the foundation for future external expansion. [1]
expand
After Omar I ascended the throne, he launched an unprecedented military and cultural conquest movement in Arab history. These movements eliminated the Persian Empire, defeated the Byzantine Empire, changed the beliefs of one-third of the inhabitants of the Old World, and permanently changed the geographical distribution of various civilizations in the Middle Ages. There are many academic opinions on the motives behind the launch of the Great Conquest by Umar I, but there are several points that all researchers agree with: the various interest groups on the Arabian Peninsula appear to be unified under the banner of the new moon, but in reality, their tribal, clan, and class conflicts are complex and intertwined. The Bedouin people are fierce and skilled in warfare, but their nature of disliking discipline also adds instability to the newly emerging country. The best solution to resolve these contradictions is to launch a foreign war, combining the interests of the rebellious tribes and clans with those of the rulers of Medina, and consolidating and developing the military and political alliance of the Arabs in solidarity. At the same time, the dissemination of Islam as the banner of foreign wars is in line with the Islamic doctrine under the banner of Allah, which encourages more people to convert to it.

In 635 AD, Arab soldiers divided into two routes and launched a comprehensive attack on the Byzantine and Persian empires. Under the leadership of General Khalid, known as the "Sword of Allah," the Western Army quickly passed through the remote Syrian desert and annihilated 50000 Byzantine troops on the banks of the Yamuk River, occupying the Syrian capital Damascus.
The victory of the Battle of Yamuk greatly stimulated the Arab desire for expansion. Syria holds an important strategic position, as it can advance eastward into Persia and northward to control Central Asia. Syria itself is also a prosperous and fertile land.
After occupying Syria, the Arabs took advantage of their victory and marched eastward. Under the heavy blow of General Said, the decaying Sassanid Persian Empire, like withered bamboo, quickly collapsed.
In the Battle of Cartesian in 636 AD, the Arab army defeated the Persian army and occupied Iraq in one fell swoop.
Later, through the Battle of Jalula in 637 AD, the Arab army was able to occupy Upper Mesopotamia and enter the Iranian plateau, penetrating deep into the Persian hinterland.
In 642 AD, the Battle of Nehavin completely defeated the last Persian army and eliminated the Persian Empire, which had a history of over 1200 years of civilization (from the Sassanid dynasty onwards, it was also an empire of over 400 years).
At the same time, the Western Army led by the famous commander-in-chief Amur ibn As. In 640 AD, the Arab army invaded Byzantine Egypt and achieved a great victory in the Battle of Heliopolis. Alexander was captured in 641 AD and Cairo was occupied in 642 AD. From then on, Egypt, the "granary of the Byzantine Empire," was permanently incorporated into the territory of the Caliphate Empire. [1]

Strategic talent
In the era of cold weapons in which Omar lived, nomadic peoples had an inherent advantage in war over agricultural peoples, while the Byzantine and Persian empires, which had been oppressing the Arabs, were engaged in a prolonged battle, both of which were exhausted. The Arabs organized by the Islamic faith, on the other hand, are as fierce as tigers descending the mountain. Omar had a strategic vision and was always able to invest his army in the right area at the right time, enabling a group of outstanding military leaders to showcase their talents, such as Khalid, Amur bin Az, and Said bin Abi Wakas, all of whom became the backbone of the empire's expansion. Omar is also an outstanding organizer and mobilizer, fully tapping into the combat energy of the tribal people, using abundant spoils of war as stimuli to inspire soldiers to move forward and fight bravely against the enemy. At the same time, Omar provided relatively lenient religious and economic policies to the people of the newly conquered areas, which made them more receptive to Islam and willing to contribute to the establishment of the Islamic Empire under the leadership of Muslims.
be assassinated
In the year 644 AD, just as Omar's external expansion was in full swing and victories were constantly coming from the front line, on the early morning of November 13th, Omar was assassinated by a pagan and died despite being cured. Omar died, but the expansion of Islamic foreign military culture initiated by Omar did not stop with his death, and its development momentum did not come to an end until around 750 years later. [1]

The 10 years of Omar's external expansion were a decade of Arab dominance, as well as a decade of Muslim community organizations growing and gradually moving towards the era of empire. In Islamic history, Omar's influence on Arab historical and cultural processes is second only to that of the Prophet Muhammad. As the founder of the Arab Islamic Empire, Omar's contributions and status in human history can be compared to those of Emperor Constantine the Great, Emperor Qin Shi Huang, and King Ashoka.