Affinity to Muḥammad was also considered. "By God," exclaimed ‘Umar, "we have not won superiority in this world, nor do we hope for recompense for our works from God hereafter, save through Muḥammad (God bless him and grant him peace!). He is our title to nobility, his tribe are the noblest of the Arabs, and after them those are the nobler that are nearer to him in blood. Truly, the Arabs are ennobled by God's Apostle. Peradventure some of them have many ancestors in common with him, and we ourselves are only removed by a few forbears from his line of descent, in which we accompany him back to Adam. Notwithstanding this, if the foreigners bring good works and we bring none, by God, they are nearer to Muḥammad on the day of Resurrection than we. Therefore let no man regard affinity, but let him work for that which is in God's hands to bestow. He that is retarded by his works will not be sped by his lineage."[360] It may be said of ‘Umar, not less appropriately than of Cromwell, that he "cast the kingdoms old Into another mould;" and he too justified the poet's maxim-- "The same arts that did gain A power, must it maintain." [Sidenote: Foundation of Baṣra and Kúfa (638 A.D.).] Under the system which he organised Arabia, purged of infidels, became a vast recruiting-ground for the standing armies of Islam: the Arabs in the conquered territories formed an exclusive military class, living in great camps and supported by revenues derived from the non-Muḥammadan population. Out of such camps arose two cities destined to make their mark in literary history--Baṣra (Bassora) on the delta of the Tigris and Euphrates, and Kúfa, which was founded about the same time on the western branch of the latter stream, not far from Ḥíra. [Sidenote: Death of ‘Umar (644 A.D.)] ‘Umar was murdered by a Persian slave named Fírúz while leading the prayers in the Great Mosque. With his death the military theocracy and the palmy days of the Patriarchal Caliphate draw to a close. The broad lines of his character appear in the anecdotes translated above, though many details might be added to complete the picture. Simple and frugal; doing his duty without fear or favour; energetic even to harshness, yet capable of tenderness towards the weak; a severe judge of others and especially of himself, he was a born ruler and every inch a man. Looking back on the turmoils which followed his death one is inclined to agree with the opinion of a saintly doctor who said, five centuries afterwards, that "the good fortune of Islam was shrouded in the grave-clothes of ‘Umar b. al-Khaṭṭáb."[361] [Sidenote: ‘Uthmán elected Caliph (644 A.D.).] [Sidenote: General disaffection.] [Sidenote: ‘Uthmán murdered (656 A.D.).]