Complex sentence: Prominent among the roughly hundred people in attendance were the Chief of Mission of Belgium, Baron Albert D'Anethan, and his wife, the Baroness, who was one of the committee of nine Japanese and European men and women voted into office.
Split into simpler sentences: Prominent among the roughly hundred people in attendance were the Chief of Mission of Belgium, Baron Albert D'Anethan, and his wife, the Baroness. She was one of the committee of nine Japanese and European men and women voted into office.