Complex sentence: The WBO sanctioned a fight between two relatively unknown fighters, Francesco Damiani and Johnny DuPlooy, to determine the initial holder of its heavyweight title in 1989, although all other sanctioning bodies of boxing recognized Mike Tyson as the heavyweight champion at the time.
Split into simpler sentences: The WBO sanctioned a fight between two relatively unknown fighters, Francesco Damiani and Johnny DuPlooy, to determine the initial holder of its heavyweight title in 1989. All other sanctioning bodies of boxing recognized Mike Tyson as the heavyweight champion at the time.