The conquest of Africa, though not nearly so advantageous to the commerce of the Arabians, was yet of some importance to them in this point of view:  it gradually extended from the Nile to the Atlantic Ocean.  Tripoly was the first maritime and commercial city which their arms reduced:  Bugia and Tangier were next reduced.  Cairoan was formed as a station for a caravan; a city, which, in its present decay, still holds the second rank in the kingdom of Tunis.  Carthage was next attacked and reduced; but an attempt was made by forces sent from Constantinople, joined by the ships and soldiers of Sicily, and a powerful reinforcement of Goths from Spain, to retake it.  The Arabian conquerors had drawn a strong chain across the harbour; this the confederate fleet broke:  the Arabians for a time were compelled to retreat; but they soon returned, defeated their enemies, burnt Carthage, and soon afterwards completed the conquest of this part of Africa.

The beginning of the eighth century is remarkable for their invasion of Spain, and for their second fruitless attack on Constantinople; during the latter, their fleet, which is said to have consisted of 1800 vessels, was totally destroyed by the Greek fire.  With regard to their conquest of Spain, it was so rapid, that in a few months the whole of that great peninsula, which for two centuries withstood the power of the Roman republic at its greatest height, was reduced, except the mountainous districts of Asturia and Biscay, Here also the Arabians displayed the same attention to science by which they were distinguished in Asia:  ten years after the conquest, a map of the province was made, exhibiting the seas, rivers, harbours, and cities, accompanied with a description of them, and of the inhabitants, the climate, soil, and mineral productions.  “In the space of two centuries, the gifts of nature were improved by the agriculture, the manufactures, and the commerce of an industrious people.”  The first of the Ommiades who reigned in Spain, levied on the Christians of that country, 10,000 ounces of gold, 10,000 pounds of silver, 10,000 houses, &c.  “The most powerful of his successors derived from the same kingdom the annual tribute of about six millions sterling.  His royal seat of Cordova contained 600 mosques, 900 baths, and 200,000 houses:  he gave laws to 80 cities of the first order, and to 300 of the second and third:  and 12,000 villages and hamlets were situated on the banks of the Guadalquivir.”

The religious prejudices, as well as the interests of the Arabians, led them to exclude the Christians from every channel through which they had received the produce of India.  That they were precluded from all commercial intercourse with Egypt, is evident, from a fact noticed by Macpherson, in his Annals of Commerce.  Before Egypt was conquered by the Arabians, writings of importance in Europe were executed on the Egyptian papyrus; but after that period, at least till the beginning of the ninth century, they are upon parchment.—­This, as Macpherson observes, amounts almost to a proof, that the trade with Egypt, the only country producing papyrus, was interrupted.