Complex sentence: Ramiro II ("c." 900--951), King of León (931--951), son of Ordoño II, was the creator of a Navarrese, Leonine and Aragonese coalition that defeated the Muslims in the Battle of Simancas (939).
Split into simpler sentences: Ramiro II ("c." 900--951), son of Ordoño II, was King of León from 931 until his death. Ramiro was the creator of a Navarrese, Leonine and Aragonese coalition that defeated the Muslims in the Battle of Simancas (939).