Complex sentence: Walnut, a son of Highflyer, never raced after an accident which left him with a "wasted" foreleg, sired several other good horses including Constantia, the dam of the St Leger winner Ebor.
Split into simpler sentences: Walnut, a son of Highflyer, never raced after an accident which left him with a "wasted" foreleg. He sired several other good horses including Constantia, the dam of the St Leger winner Ebor.