Complex sentence: After his return to Graz, Denifle taught philosophy and theology for ten years (1870--1880), and during this period also he was recognized as one of the best preachers in Austria.
Split into simpler sentences: After his return to Graz, Denifle taught philosophy and theology for ten years (1870--1880). During the period of his teaching in Graz he was recognized as one of the best preachers in Austria.