Prince of Orange intervened, and told the university not to be silly. This illustrates the gain to
Protestant countries from the subordination of the Church to the State, and from the comparative
weakness of Churches that were not international.
Unfortunately, through Chanut, the French ambassador at Stockholm, Descartes got into
correspondence with Queen Christina of Swed.en, a passionate and learned lady who thought that,
as a sovereign, she had a right to waste the time of great men. He sent her a treatise on love, a
subject which until then he had somewhat neglected. He also sent her a work on the passions of
the soul, which he had originally composed for Princess Elizabeth, daughter of the Elector
Palatine. These writings led her to request his presence at her court; he at last agreed, and she sent
a warship to fetch him ( September 1649). It turned out that she wanted daily lessons from him,
but could not spare the time except at five in the morning. This unaccustomed early rising, in the
cold of a Scandinavian winter, was not the best thing for a delicate man. Moreover Chanut
became dangerously ill, and Descartes looked after him. The ambassador recovered, but Descartes
fell ill and died in February 1650.
Descartes never married, but he had a natural daughter who died at the age of five; this was, he
said, the greatest sorrow of his life. He always was well dressed, and wore a sword. He was not
industrious; he worked short hours, and read little. When he went to Holland he took few books
with him, but among them were the Bible and Thomas Aquinas. His work seems to have been
done with great concentration during short periods; but perhaps, to keep up the appearance of a
gentlemanly amateur, he may have pretended to work less than in fact he did, for otherwise his
achievements seem scarcely credible.
Descartes was a philosopher, a mathematician, and a man of science. In philosophy and
mathematics, his work was of supreme importance; in science, though creditable, it was not so
good as that of some of his contemporaries.
His great contribution to geometry was the invention of co-ordinate geometry, though not quite in
its final form. He used the analytic method, which supposes a problem solved, and examines the
consequences of the supposition; and he applied algebra to geometry. In both of these he had had
predecessors--as regards the former, even