That his treatises were in urgent need of a competent editor is apparent from the observations which Porphyry makes with regard to his methods of composition. He was in the habit of writing down his thoughts just as they occurred to him, and “could not (says his biographer) by any means endure to review twice what he had written, nor even to read his own composition,” mainly on account of his defective eyesight. Nor, indeed, was he by any means a perfect master of the Greek language, in which his lectures were delivered and his books written. Porphyry in fact observes, let us hope with some exaggeration, that he “neither formed the letters with accuracy, nor exactly distinguished the syllables, nor bestowed any diligent attention on the orthography, but neglecting all these as trifles, he was alone attentive to the intellection of his wonderful mind, and, to the admiration of all his disciples, persevered in this custom to the end of his life.” One is, indeed, not a little impressed how entirely, in the later days of the Roman Empire, “captive Greece led captive her conquerors.” Greek philosophy and Greek ideas had, in truth, permeated the whole civilised world. Not only was this the case, but when the Western or Roman Empire fell eventually into decrepitude and ruin, its Eastern partner, though threatened and harassed by barbarian foes on all its borders, continued to survive the extinction of the erstwhile mistress of the world by something like a thousand years. Alexandria was, however, destined to destruction by an Arab invasion long ere this, and never recovered from its sack by the Mohammedan Amru in A.D. 640. The survival of the Eastern Empire was doubtless due in great part to the superior vitality of the Greek race; but it does not admit of doubt that it would have fallen a victim to the Moslem invader at least 500 years before the date of its final doom, had it not been for Constantine’s choice of an Eastern capital and the almost impregnable position enjoyed by the imperial city. It is open to conjecture that had the British Government of the present day been better acquainted with the history of Constantinople and the many sieges which it had successfully sustained, they would have thought twice, and indeed thrice, before launching without adequate preparation, the ill-fated expedition to the Dardanelles.