Complex sentence: As with all sports the actual contenders know how they wanted to play and were reluctant to give up the purity that bare knuckle boxing had and was then banned again in most parts of the world in the nineteenth century.
Split into simpler sentences: As with all sports the actual contenders knew how they wanted to play and were reluctant to give up the purity that bare knuckle boxing had. Nonetheless, bare knuckle boxing was banned again in most parts of the world in the nineteenth century.