Complex sentence: He was most notable for his defeat by better trained and superior forces under the formidable Frederick the Great at the Battle of Chotusitz in 1742 and more decisively at the Battle of Hohenfriedberg in 1745.
Split into simpler sentences: He was most notable for his defeats by better trained and superior forces under the formidable Frederick the Great. However, he lost more decisively to Frederick at the Battle of Hohenfriedberg in 1745.