  While Leibniz was living the life of the mind in Paris, his employer died, and Leibniz was thus forced to look for another position. He eventually found one as the librarian for Duke Johann Friedrich of Brunswick, who ruled in Hanover. On the way to Hanover, Leibniz stopped in Amsterdam to meet with Spinoza between November 18 and 21, 1676, three months before the latter's death; according to Leibniz's own notes, they spoke of Spinoza's yet-to-be-published Ethics, Cartesian physics, and Leibniz's improved version of the ontological argument (see below). Although Leibniz would travel to Italy for a time in the late 1680s in order to conduct historical research for the House of Hanover and make many shorter trips (including to Vienna), the rest of his life was essentially spent in Hanover and its environs, working in different capacities for the court, first, for Johann Friedrich until his death in 1680, then for Johann Friedrich's brother, Ernst August (from 1680 to 1698), and finally for the latter's son, Georg Ludwig, who in 1714 would become George I of England. Leibniz's relations with Ernst August and Georg Ludwig were not as amicable as his relations with his original employer, but he was close to Sophie, the wife of Ernst August and youngest sister of Princess Elisabeth of Bohemia, with whom Descartes had an important philosophical correspondence. (Sophie was also the daughter of Elizabeth Stuart, and it is for this reason that her son became King of England.)