The Roman _bishop_ (overseer) acquired power over all bishops in other Christian centres, and became the head of the Church with the title _pope_ (Greek-father). In the course of time these popes exercised immense power, and we shall see kings trembling before them. For they came to be regarded as the representatives of God on earth. Whoever dared oppose their will was excommunicated, i.e., cut off. Then all shrunk from the person thus put under the ban as from a person smitten with leprosy; for the superstitious age regarded him as accursed and doomed. Very terrible was it when this dangerous power was in the hands of an unscrupulous pope, which not infrequently happened. But there were many good popes, too, and the Jews found among them, as we shall see, friends as well as foes. Gregory I, one of the earliest and also one of the greatest, would not allow his bishops to molest the Jews, "whom God had found worthy to be bearers of His truth"; though he offered the bribe of remission of taxes for their conversion! Slavery and Trade. Slavery was still a recognized institution of society, due in part to constant warfare, the daily business of life and to the custom of enslaving prisoners of war. So slaves were in nearly every household and in the fields, taking the place of the humble toilers of to-day. So we find Jews holding them likewise. They often converted them to Judaism and in all cases were kinder to them than most masters. But Gregory vigorously objected--not to slavery, but to the enslaving of Christians, and particularly to the possession of Christian slaves by Jews. The Church greatly feared that by proselytizing their slaves the Jews might increase their numbers. This was to be prevented at any cost. If the question were asked why Jews came to trade in slaves, the answer would be because they were becoming traders in general, and traffic in slaves was part of the commerce of the age. It is then part of a larger question--how came the Jews to seek trade as a means of livelihood? _First_, by the law of necessity. Most other avenues of activity were being closed to them. Not permitted to own lands, they could hardly be agriculturists. Gradually the army, the public service and most of the professions were forbidden to Jews. _Secondly_, on account of their dispersion through the world, which had its compensating advantages. United to their brethren by close fraternal ties, speaking a common tongue and moving frequently from place to place, the exchange of commodities was facilitated. Then having smaller opportunities of expenditure, and in any case of moderate tastes, they naturally possessed ready means. _Lastly_, their hard fate in lands of exile, the growing precariousness of their position under fanatic powers, quickened their wits in the life struggle and endowed them with the capacities that earn success in trade. (We are not therefore surprised to learn that the Jews invented bills of exchange.)