Complex sentence: Pogorelić won the Casagrande Competition in Terni (Italy) in 1978 and the Montreal International Music Competition in 1980; but he became famous for the prize he didn't win.
Split into simpler sentences: Pogorelić won the Casagrande Competition in Terni, Italy in 1978 and the Montreal International Music Competition in 1980. However he became famous for the prize he didn't win.