Complex sentence: The Castellammarese War raged on between the Masseria and Maranzano factions for almost four years, devastating the Prohibition-era operations and street rackets that the five New York families controlled along with the Irish and Jewish crime groups.
Split into simpler sentences: The Castellammarese War raged on between the Masseria and Maranzano factions for almost four years. This internal war devastated the Prohibition-era operations and street rackets that the five New York families controlled along with the Irish and Jewish crime groups.