178 THE HISTORY OF MEDIEVAL EUROPE advancement. As a result the Copts in Egypt professed ad- herence to Islam so rapidly that the amount of the tribute fell off in the course of a few years from twelve to five mil- lions. When one had once become a Mohammedan, one could not return to one's previous faith without incurring the death penalty. The Arabs themselves did not per- manently remain fanatical or puritanical, but were often inclined to good living and to skepticism, and were easy- going in their interpretation of religious rules. They also were slow to make any great change in the governmental ma- chinery of lands which they conquered ; so long as the trib- ute came in regularly, they were content to leave Byzantine and Persian institutions much as they found them. The condition of serfs and slaves frequently improved under the Mohammedan rule of this period, and they were often emancipated by their new Arabian masters, especially if they embraced the faith of the Prophet. Because of the opposition of the wild Berber tribes as well as of the Byzantines, it took the Moslems over half a cen- Conauest of tury to conquer North Africa. Carthage did not NorA Africa fall until 697-698, and the western Berbers, whom Justinian had been unable to subdue, were not ab- sorbed by Islam until the early years of the following cen- tury. Ancient civilization now rapidly disappeared in Africa, a loss due more to the Berbers than to the Arabs or Vandals, and this once extremely prosperous region became desolate. Only the Christian Church lived on in Africa in decreasing strength for centuries. The Berber tribes, whose mode of life and state of civilization was similar to that of the nomads of the Arabian desert, for the most part accepted Islam, and many of them swept on westward in the wave of conquest. Spain was the next objective of the Moslems. A deposed king fled to them for aid against his supplanter. The Visi- Q»qd«t gothic Kingdom was also weakened by its per- secution of the Jews and by the selfish treachery of the nobles. In 711, Tarik, lieutenant of the Moslem governor of Mauretania, Musa ibn Nusair, landed near the
