"Theodor von Sickel (18 December 1826 – 21 April 1908) was a German-Austrian historian born in Aken, Province of Saxony, Kingdom of Prussia. He specialized in early European medieval history, and is considered to be the founder of modern diplomatics (critical document research).
In 1850 he obtained his doctorate from the University of Halle, then furthered his studies at the École Nationale des Chartes in Paris. In 1857 he was appointed professor at the University of Vienna, and from 1869 to 1891, he was director of the Institut für Österreichische Geschichtsforschung (Institute of Austrian Historical Research), specializing in ancillary branches of historical study, that included paleography, chronology and diplomatics." - (en.wikipedia.org 19.10.2020)