Empire Extended by Conquests of the Caliphs
Mohammed was succeeded in his power by rulers called his Caliphs, or Successors, the first of whom was his father-in-law, Abu-beker. They were at once spiritual and temporal rulers. The proselyting spirit of Mohammed had been communicated to his successors, and they began a long series of invasions, wars, and conquests. They everywhere gave men the choice of three things,—Koran, tribute, or sword. By these means the religion of Mohammed was spread over a large part of Asia and Africa, and made its way into Europe also.