Complex sentence: The 1957 World Series featured the defending champion New York Yankees (98-56) against the Milwaukee Braves (95-59), who had won their first pennant since moving from Boston in 1953.
Split into simpler sentences: The 1957 World Series featured the defending champion New York Yankees (98-56) against the Milwaukee Braves (95-59). This was the Braves first pennant since moving from Boston in 1953.