After the first fire of prophetic zeal had illuminated him, Mahomet devoted himself to the conversion of his own household and family. Khadijah was the first convert, as might have been expected from the close interdependence of their minds. She had become initiated into his prophetship almost equally with her husband, and it was her courage and firm trust in his inspiration that had sustained him during the terrible period of negation. Zeid, the Christian slave who had helped to mould Mahomet's thought by his knowledge of Christian doctrine, was his next convert, but both of these were eclipsed by the devotion to Mahomet's gospel of Ali, the future warrior, son of Abu Talib, and one destined to play a foremost part in the foundation of Islam. Mahomet's gospel then penetrated beyond the confines of his household with the conversion of his friend Abu Bekr, a successful merchant living in the same quarter of the town as the Prophet. Abu Bekr, whose honesty gained him the title of Al-Siddick (the true), and Ali were by far the most important of Mahomet's "companions." They helped to rule Islam during Mahomet's lifetime, and after his death took successive charge of its fortunes. Ali was too young at this time to manifest his qualities as warrior and ruler, but Abu Bekr was of middle age, and his nature remained substantially the same as at the inception of Islam. He was of short stature, with deep-seated eyes and a thoughtful, somewhat undecided mouth, by nature he was shrewd and intelligent, but possessed little of that original genius necessary to statesmanship in troublous times. His mild, sympathetic character endured him to his fellow-men, and his calm reasonableness earned the gratitude of all who confided in him. He was never ruled by impulse, and of the fire burning almost indestructibly within Mahomet he knew nothing. It is strange to consider what agency brought these two dissimilar souls into such close relationship. For the rest of his life Mahomet found a never-failing friend in Abu Bekr, and the attachment between the two, apart from their common fount of zeal for Islam, must have been such as is inspired by those of contrasting nature for each other. Mahomet saw a kindly, almost commonplace man, in whose sweet sanity his troubled soul could find a little peace. He was burdened at times with over-resolve that ate into his mind like acid. In Abu Bekr he could find the soothing influence he so often needed, and after the death of Khadijah this friend might be said in a measure to take her place. Abu Bekr, on the other hand, revered his leader as a man of finer, subtler stuff than himself, more alive to the virtue of speed, filled with a greater daring and a profounder impulse than he was. Mahomet, in common with most men meriting the title of great, had a capacity for lifelong friendships as well as the power of inspiring belief and devotion in others.