Jewish Encyclopedia Volume 4 p316 states:

COURT JEWS : Court Jews, called also court factors, and court or chamber agents, played a part at the courts of the Austrian emperors and the German princes in the seventeenth and eighteenth centuries and at the beginning of the nineteenth. Not always on account of their learning or their force of character did these Jews rise to positions close to the rulers: they were mostly wealthy business men, distinguished above their coreligionists by their commercial instincts and their adaptability.

Important as court Jews were also Samuel Oppenheimer, who went from Heidelberg to Vienna, and Samson Wertheimer (Wertheimher) from Worms. Oppenheimer, who was appointed chief court factor, together with his two sons Emanuel and Wolf, and Wertheimer, who was at first associated with him, devoted their time and talents to the service of Austria and the House of Hapsburg. Moses Bonaventura of Prague was also court Jew of Saxony in 1679.

The great elector also kept his court Jew at Berlin, Israel Aaron (1670), who by his influence tried to prevent the influx of foreign Jews into the Prussian capital. Other court Jews of the elector were Gumpertz (died 1672), Berenf Wulff (1675), and Solomon Frankel (1678).

After his death his influential position fell to his widow, the well-known Liebmannin, who was so well received by Frederick III. (from 1701 King Frederick I. of Prussia) that she could go unannounced into his cabinet. There were court Jews at all the petty German courts: e.g., Zacharias Seligmann (1694) in the service of the Prince of Hesse-Homburg, and others in the service of the dukes of Mecklenburg.

The last actual court Jews were Israel Jacobson, court agent of Brunswick, and Wolf Breidenbach, factor to the Elector of Hesse, both of whom occupy honorable positions in the history of the Jews.