Their remains were buried at Soissons, but were afterwards removed, partly by Charlemagne to Osnabruck (where a festival is observed annually on the 10th of June) and partly to the chapel of St Lawrence in Rome.
The court of Vienna had treated the Silesian Protestants with tyrannical severity, in direct contravention of the treaty of Osnabruck, of which Sweden was one of the guarantors; and Charles demanded summary and complete restitution so dictatorially that the emperor prepared for war.
He was educated at the Carolinum, an endowed school at Osnabruck, and studied at the universities of Gottingen and Heidelberg.
Windthorst's Ausgewahlte Reden were published in three volumes (Osnabruck, 1901-1902).
For a few years he was a teacher at Leer and at Osnabruck; but in 1858 he settled at Hanover, where he became intimate with King George V., who made him his Archivrat.