Complex sentence: Due to lack of reliable documentation there is a great degree of debate over Waldo's role in the Waldensian sect which may have existed before his leadership, while the French historian Thuanus dated his death to the year 1179.
Split into simpler sentences: Due to lack of reliable documentation there is a great degree of debate over Waldo's role in the Waldensian sect, which may have existed before his leadership. The French historian Thuanus dated his death to the year 1179.