Johann Tserclaes mercenary Johann Tilly loyally served a series of European leaders for more than a half century, earning a reputation as a staunch, brave leader who exhibited superior tactical and strategic skills. For much of the Thirty Years’ War, Tilly commanded the Catholic League forces in a consistent string of victories. Ully became one of the dominant generals of his time by mastering in- 1 fan try fighting formations. His only significant fault was that he oudived the style of warfare in which he was so proficient.<\/p>