Complex sentence: From 1761 to 1763 he officiated as secretary of the Austrian "Arcierengarde", and in the latter year was appointed professor of political science at the University of Vienna, twice acting as rector magnificus.
Split into simpler sentences: From 1761 to 1763 he officiated as secretary of the Austrian "Arcierengarde". In 1763, he was appointed professor of political science at the University of Vienna, twice acting as rector magnificus.