Nothing better shows modern Islam's quickened vitality than the revival of missionary fervour during the past hundred years. Of course Islam has always displayed strong proselytizing power. Its missionary successes in its early days were extraordinary, and even in its period of decline it never wholly lost its propagating vigour. Throughout the Middle Ages Islam continued to gain ground in India and China; the Turks planted it firmly in the Balkans; while between the fourteenth and sixteenth centuries Moslem missionaries won notable triumphs in such distant regions as West Africa, the Dutch Indies, and the Philippines. Nevertheless, taking the Moslem world as a whole, religious zeal undoubtedly declined, reaching low-water mark during the eighteenth century. The first breath of the Mohammedan Revival, however, blew the smouldering embers of proselytism into a new flame, and everywhere except in Europe Islam began once more advancing portentously along all its far-flung frontiers. Every Moslem is, to some extent, a born missionary and instinctively propagates his faith among his non-Moslem neighbours, so the work was carried on not only by priestly specialists but also by multitudes of travellers, traders, and humble migratory workers.[35] Of course numerous zealots consecrated their lives to the task. This was particularly true of the religious fraternities. The Sennussi have especially distinguished themselves by their apostolic fervour, and from those natural monasteries, the oases of the Sahara, thousands of "Marabouts" have gone forth with flashing eyes and swelling breasts to preach the marvels of Islam, devoured with a zeal like that of the Christian mendicant friars of the Middle Ages. Islam's missionary triumphs among the negroes of West and Central Africa during the past century have been extraordinary. Every candid European observer tells the same story. As an Englishman very justly remarked some twenty years ago: "Mohammedanism is making marvellous progress in the interior of Africa. It is crushing paganism out. Against it the Christian propaganda is a myth."[36] And a French Protestant missionary remarks in similar vein: "We see Islam on its march, sometimes slowed down but never stopped, towards the heart of Africa. Despite all obstacles encountered, it tirelessly pursues its way. It fears nothing. Even Christianity, its most serious rival, Islam regards without hate, so sure is it of victory. While Christians dream of the conquest of Africa, the Mohammedans do it."[37]