Complex sentence: Estrangement between husband and wife escalated from discrete and simmering hostilities into open armed warfare between the Leonese-Castilians and Aragonese; however, by the fall of 1112 a truce was brokered between Urraca and Alfonso with their marriage annulled.
Split into simpler sentences: Estrangement between husband and wife escalated from discrete and simmering hostilities into open armed warfare between the Leonese-Castilians and the Aragonese. By the fall of 1112 a truce was brokered between Urraca and Alfonso with their marriage annulled.