Causes of Muslim success. How the Muslims were able to overpower the gigantic empires of Persia and Byzantium is one of the great mysteries of history. Various western writers have tried to discover in their own way the causes of the astounding success of the Muslims. They have referred to four main causes, namely racial, political, economic and moral.
Racial affinity. Von Kremer has observed as follows in his book The Orient under Caliphs: "Instead of fighting their powerful kinsmen, the people of the frontier towns who were in the play either of the Byzantine or the Persian empire found it much more to their advantage to make common cause with the Arabs. It was thus that a comparatively smaller army which penetrated Syria and Iraq quickly grew like an avalanche, and crushed down all obstacles that stood in its way."
In his book, The age of Faith, Will Durant has held that the racial factor was an important cause of the success of the Muslims, as both Syria and Iraq contained Arab tribes who had much in common with the Muslims.
In their book, World History, Flenley and Welch have held that the racial affinity of the people made the extension of the Muslim rule easier.
When Abu Bakr undertook campaigns in Iraq and Syria, these campaigns were really not directed against the Byzantine or Persian empires; these were really directed to bring the Arabs living in Iraq and Syria to the fold of Islam. In the wars in Iraq and Syria many Christian Arabs fought against the Muslims, but many of them sided with the Muslims as well. We can thus concede that in the success of the Muslim arms in Iraq and Syria, Arab nationalism played its part.
Political cause. Will Durant has held, in his book The Age of Faith, the political cause of the success of the Muslims was that both Byzantium and Persia exhausted by war and mutual devastation were in a state of decline.
In his book The History of the World H. G. Wells has observed as follows: "It (Islam) prevailed because every where it found politically apathetic people, robbed, oppressed, bullied, uneducated and unorganized and it found selfish and unsound governments out of touch with the people." In their World History, Flenley and Weleh have also held that the political cause of the success of Muslims was that the Persian and Byzantine empires stood exhausted by mutual wars.
This analysis of the political situation is basically correct, and we can very well hold that when Islam appeared on the scene, these old empires were in the process of decline.