Complex sentence: But football wasn't the only sport Raoul Daufresne de la Chevalerie was practising, he was also an equestrianist, he played hockey and tennis and he was coach of the Belgian football team at the 1920 Summer Olympics in Antwerp.
Split into simpler sentences: But football wasn't the only sport Raoul Daufresne de la Chevalerie was practising. He was also an equestrianist, he played hockey and tennis and he was coach of the Belgian football team at the 1920 Summer Olympics in Antwerp.