Complex sentence: Together with Peter Habeler, Messner succeeded in making the second ascent of Gasherbrum I on 10 August 1975, becoming the first man ever to climb more than two eight-thousanders.
Split into simpler sentences: Together with Peter Habeler, Messner succeeded in making the second ascent of Gasherbrum I on 10 August 1975. With this ascent, Messner became the first man ever to climb more than two eight-thousanders.