Complex sentence: Loyal bishops were granted military protection and other imperial favours and could become extremely powerful rulers in their own right but tension between the Empire and the Roman Catholic Church such as during the Investiture Controversy of 1075, could lead to damaging conflicts of loyalty.
Split into simpler sentences: Loyal bishops were therefore granted extensive military protection and other imperial favours and could become extremely powerful rulers in their own right. However, tension between the Empire and the Roman Catholic Church such as during the Investiture Controversy of 1075, could lead to damaging conflicts of loyalty.