Complex sentence: In December 1967 Phoenix had their first major series of concerts in many western cities, capped off by two huge concerts in Timişoara, and in April 1968 they won the first national rock competition in Iaşi.
Split into simpler sentences: In December 1967 Phoenix had their first major series of concerts in many western cities, capped off by two huge concerts in Timişoara. In April 1968 they won the first national rock competition in Iaşi.