Franz Kasimir von Kleist (25 January 1736 – 30 March 1808) was an infantry general of the Kingdom of Prussia.
After the capitulations of Prenzlau, Stettin, Spandau and Küstrin Kleist thought resistance pointless and felt himself forced to surrender the fortress on 8 November 1806 to Marshal Ney, with approximately 24,000 men, 600 guns and great quantities of supplies.
This surrender without any fighting was extremely controversial then as now: the fortress was given up after a siege of only three weeks and despite the fact that the defenders outnumbered the invading French troops.
[1] Kleist's conduct was the subject of the Immediatuntersuchungskommission, the commission of investigation held by Prussia into the humiliating defeat of its army in the War of the Fourth Coalition of 1806–07.
The commission met by order of King Frederick William III of Prussia from 27 November to 6 December 1807 and continued working until 1812.