It is remarkable that the Jews had become indispensable to the Christian population, in spite of the venomous hatred with which the latter regarded them. Not only princes, but cities, and even the clergy, had a mania for "possessing Jews." A few years after the terrible frenzy which followed the Black Death, German citizens and their magistrates hastened to re-admit the Jews; they soon forgot their vow, that for a hundred or two hundred years no Jew should dwell within their walls. The bishop of Augsburg applied to Emperor Charles IV for the privilege "to receive and harbor Jews." The electors, ecclesiastical as well as secular, were bent upon curtailing the exclusive right of the German emperor to possess serfs of the chamber (servi cameræ), and upon acquiring the same right for themselves. Gerlach, archbishop of Mayence, especially exerted himself to wrest this privilege from Emperor Charles IV, his success being to no small extent due to the desire of the emperor to retain his popularity amongst the electors. At an imperial Diet held at Nuremberg in November, 1355, where a kind of German constitution, known as the "Golden Bull," was promulgated, the emperor conferred on the electors, in addition to the right of discovery of metal and salt mines, the privilege to hold Jews; that is to say, he yielded to them this source of revenue in addition to such sources as deposits of metal and salt. But it was only to the electors that the emperor conceded this right; he retained his rights over the "servi cameræ" living under the rule of the minor princes and in cities. The archiepiscopal elector of Mayence lost no time in utilizing the new privilege, and immediately employed a Jew to obtain others for him. Thus the Jews were at once repelled and attracted, shunned and courted, outlawed and flattered. They were well aware that it was not for their own sake that they were tolerated, but solely on account of the advantages they afforded the authorities and the population. How, then, could they be expected not to devote themselves to money-making, the sole means by which they were enabled to drag out a miserable existence?