Complex sentence: A baritone he initially sang for the Boston Opera He did not abandon his native Poland working with Paderewiski to raise over $500,000 for Poland and recruit for the Polish army during World War One.
Split into simpler sentences: A baritone he initially sang for the Boston Opera but he did not abandon his native Poland. He worked with Paderewiski to raise over $500,000 for Poland and recruited men for the Polish army during World War One.