Complex sentence: Chief among Jeune's successful offspring was the gutsy and ill-fated 2003 Caulfield Cup winner Mummify and On A Jeune, who ran second in the Melbourne Cup.
Split into simpler sentences: Chief among Jeune's successful offspring was the gutsy and ill-fated 2003 Caulfield Cup winner Mummify. He sired On A Jeune, who ran second in the Melbourne Cup.