Within a hundred years after the death of Justinian, an event happened, which occasioned a revolution still more considerable in the intercourse of Europe with the East. A prophet and a conqueror arose in Arabia; and within forty years of his death a great part of Asia, and Africa, with no inconsiderable portion of Europe, had been subdued, and the dominion of the followers of Muhammed extended from the shores of the Atlantic to the frontier of China, with a rapidity of success to which there is nothing similar in the history of mankind. “Egypt,” remarks Dr. Robertson, “was one of their earliest conquests; and, as they settled in that inviting country, and kept possession of it, the Greeks were excluded from all intercourse with Alexandria, to which they had long resorted as the chief mart of Indian goods. Nor was this the only effect which the progress of the Muhammedan arms had upon the commerce of Europe with India. Prior to the invasion of Egypt, the Arabians had subdued the great kingdom of Persia, and added it to the empire of the Khalifs.”[282] [Sidenote: The extent of their commerce with the East.] Finding their new subjects engaged in the trade with India, and sensible of the vast advantages to be derived from it, the Muhammedan rulers turned their attention to it with even greater vigour than ever the Persians had done; and pursuing the same course they had followed, their enterprising merchants soon advanced far beyond the boundaries of ancient navigation as known to the nations of the West, bringing many of the most precious commodities of the East directly from the countries in which they were produced. Having founded the city of Bussorah on the western banks of the great stream formed by the junction of the Euphrates and Tigris, they thus secured the command of these two rivers, so that this entrepôt soon became the seat of a maritime commerce second only to Alexandria in its greatest prosperity. Although their knowledge of navigation scarcely exceeded that which the Phœnicians possessed when they launched their expeditions from Gerrha some two thousand years before, the followers of Muhammed had extended, as early as the ninth century, their voyages beyond the Gulf of Siam, carrying on with Sumatra, and other islands of the Indian Archipelago, a regular commerce, and extending their trading operations even to the city of Canton. At many of the intervening ports numerous Arabian merchants and ship-owners settled with their families, so that the Arabian language was understood, and spoken at most places of any importance between the mouths of the Euphrates and Tigris, and Canton.[283]