ANCILLON, JOHANN PETER FRIEDRICH (1766 1837), Prussian historian and statesman, great-grandson of Charles Ancillon, was born at Berlin, April 3o 1766. He studied theology at Geneva, and after finishing his course was appointed minister to the French community at Berlin. Ancillon wrote a Tableau des revolutions du systeme politique de l'Europe depuis le X V e siecle (1803 ; new ed. 1824) , which gained him the eulo gium of the Institute of France, and admission to the Academy of Berlin. It was the first attempt to recognize psychological factors in historical movements, but otherwise its importance was exaggerated. In 1808 he was appointed tutor to the royal princes, in 18og councillor of state in the department of religion, and in 1810 tutor of the Crown Prince (afterwards Frederick William IV.), on whose sensitive and dreamy nature he was to exercise a powerful but far from wholesome influence. In Oct. 1814, when his pupil came of age, Ancillon was included by Prince Harden berg in the ministry, with a view to utilizing his supposed gifts as a philosophical historian in the preparation of the projected Prus sian Constitution. But the practical difficulty of the constitutional problem gave the "court parson"—as Gneisenau had contemptu ously called him—excuse enough for a change of front which, incidentally, would please his exalted patrons. He became the soul of the reactionary movement at the Berlin court, and the faithful henchman of Metternich in the general politics of Ger many and of Europe.
In 1818 Ancillon became director of the political section of the ministry for foreign affairs under Count Bernstorff, and in the spring of 1832, on Bernstorff's retirement, succeeded him as head of the ministry. Ancillon had convinced himself that the rigid class distinctions of the Prussian system were the philo sophically ideal basis of the State, and that representation "by estates" was the only sound constitutional principle; his last and indeed only act of importance as minister was his collabora tion with Metternich in the Vienna Final Act of June 12 1834, the object of which was to rivet this system upon Germany for ever. He died on April 19 1837, the last of his family. His his torical importance lies neither in his writings nor in his political activity, but in his personal influence at the Prussian court, and especially in its lasting effect on the character of Frederick William IV.
See C. A. L. P. Varnhagen von Ense, Blatter aus der preussischen Geschichte (Leipzig, 1868-69) ; ib. Tagebiicher, vol. i. (Leipzig, 1861) ; H. O. Treitschke, Deutsche Geschichte (Leipzig, 1879-94), and essay on Ancillon in Preussische Jahrbiicher for April 1872 ; Allgemeine• Deutsche Biographie, s.v. (Leipzig, 1875).