Thus, good leadership on the part of the sultan as a military leader was important to the development of the Ottoman Empire. .
Although leadership was a crucial factor, the influence of religion also contributed to the growth of the Ottoman Empire by acting as a justification for warfare. With reference to Islamic quotes like Qur'an:8:39 "So, fight them till all opposition ends and the only religion is Islam.", we can infer that religion was used as a rallying cry for troops to justify warfare as a means to accomplish their holy goal of spreading Islam. The fight between the Byzantines and the ottomans for instance was a perfect example in which both sides used religion to justify war. From the Ottomans' perspective, they were waging a holy war to spread and prove Islam's superiority over Christianity (Byzantines). The divine nature of their mission raised the morale and sense of purpose of the fighting men as fighting in the name of God was perceived an honourable duty they strove to fulfil to the very best of their abilities. The unifying force of religion is especially evident in that the Ottomans, left as the major Muslim rivals of Byzantium, attracted masses of nomads and urban unemployed who were roaming through the Middle East searching for not only means to gain their livelihoods and but also to fulfill their religious desire to expand the territory of Islam. As such, in the name of fighting for Islam, the Ottomans were able to build their army despite their limited manpower as constrained by their nomadic beginnings. Other instances of religion used as a justification for war include the fall of Constantinople in 1453 where Mehmed, in an effort to further glorify the city as Islamic territory, built several mosques, thus officially claiming the territory for Islam and hence proving the religious nature of warfare led by the inam (religious leder, protector of Islam).
