Complex sentence: Since the official formation of the Ivy League in 1956 Penn and Princeton have each won 30 games but since 1982 however, Penn has defeated Princeton 23 times and Princeton has defeated Penn in 11 games.
Split into simpler sentences: Since the official formation of the Ivy League in 1956 Penn and Princeton have each won 30 games. Since 1982 however, Penn has defeated Princeton 23 times and Princeton has defeated Penn in 11 games.