Complex sentence: He debuted in 1769 when he was 19, and until he died at the age of 45 because of a flu when he was still an active wrestler, he wrestled in 70 tournaments in total and only lost 20 battles.
Split into simpler sentences: He debuted in 1769 when he was 19, and he was still an active wrestler when he died at the age of 45 of influenza. He wrestled in 70 tournaments in total and only lost 20 battles.