How did Gottfried Wilhelm Leibniz serve as historian for the house of Brunswick?

In 1685, Gottfried Wilhelm Leibniz was appointed historian for the house of Brunswick and named Hofrat (court adviser). His primary objective was to use genealogy to prove that the princely house originated from the house of Este, an Italian family, which would enable Hanover to claim a ninth electorate.1

To gather the necessary documentation, Leibniz traveled extensively through Germany, Austria, and Italy between 1687 and 1690. His efforts were successful, as Ernest Augustus secured the electoral investiture in 1692.1

Leibniz continued his duties as historian for the remainder of his life, though he expanded his scope significantly. He pursued a project of "universal history" that incorporated geological events, fossil descriptions, linguistics, and the origins of peoples, sciences, and ethics. Additionally, he served as a jurist and historian by developing arguments regarding the rights of the house of Brunswick concerning the British succession, which eventually led to George Louis ascending the English throne as George I.1