Complex sentence: After a brilliant amateur career, culminating in the gold medal in European Amateur Boxing Championships in Belgrade, he turned professional in 1977, and won the European Boxing Union title in the light welterweight in 1979.
Split into simpler sentences: After a brilliant amateur career, culminating in the gold medal in European Amateur Boxing Championships in Belgrade. He turned professional in 1977, and won the European Boxing Union title in the light welterweight in 1979.