Johann Franz Graf von Gronsfeld-Bronckhorst (1640 – 8 April 1719) was an Imperial military officer, President of the Imperial War Council (Hofkriegsratspräsident), and Field Marshal in the Habsburg army, notably involved in the Bavarian uprising of 1705–1706.
Biography
He was the son of Jost Maximilian von Bronckhorst-Gronsfeld (1598–1662) and Anna Christina von Hardenrath (1615–1692). He was first married in 1677 to Eleonora Philippine Katharine von Fürstenberg; the marriage remained childless. His second marriage was to Anna von Törring-Ilchenbach, with whom he had a daughter who died young.
Military Career
Gronsfeld served as a Swabian general constable in 1689. He was promoted to general field sergeant (Generalfeldwachtmeister) in the Habsburg Army on 5 June 1688, to field marshal lieutenant (Feldmarschallleutnant) on 10 July 1692, to General of Cavalry on 15 September 1692, and finally to Imperial field marshal on 1 August 1704.
During the Bavarian uprising of 1705–1706, on 15 May 1705, Gronsfeld approached the city of Munich with 8,000 men and siege guns, demanding its immediate surrender under threat of bombardment. After negotiations with the government and city council, and having given written assurance that the sons of Elector Maximilian II Emanuel would be protected and that citizens would retain their privileges, the city was handed over to Imperial troops on 16 May 1705. Gronsfeld marched into Munich with 2,816 soldiers.
Divergences between the Imperial administration in Bavaria and the military command led to Gronsfeld's dismissal following a letter of complaint to Emperor Joseph I on 6 June 1705. His successor was General Count Scipioni Bagni.
Cryptography
As early as 1665, on a journey from Mainz to Frankfurt, Gronsfeld allegedly suggested the polyalphabetic encryption method named after him (the Gronsfeld cipher) to the writer and Jesuit priest Gaspar Schott. The Gronsfeld cipher is a variant of the Vigenère cipher that uses a numeric key (digits 0–9) instead of a letter key.
Death and Succession
After Gronsfeld's death, the earldom passed to his widow, who married Count Claudius Nikolaus von Arberg und Valengin. The next heiress was their daughter Maria Josepha, who married Count Max Emanuel von Toerring-Jettenbach. The marriage remained childless, and the Törring family lost the county with the German mediatisation of 1803, receiving the Imperial Gutenzell Abbey in return.
