Complex sentence: By the time of the rematches the social climate in America had settled down, with The Vietnam War coming to an end many dismissed the notion that Ali was a traitor and he was once again accepted as an American hero.
Split into simpler sentences: By the time of the rematches the social climate in America had settled down, with the Vietnam War coming to an end. Many dismissed the notion that Ali was a traitor and he was once again accepted as an American hero.