Complex sentence: He received the County of Verdun in 1096, but he soon joined the crusader army of his brother, Godfrey of Bouillon and became one of the most successful commanders of the First Crusade.
Split into simpler sentences: He received the County of Verdun in 1096, but he soon joined the crusader army of his brother, Godfrey of Bouillon. Baldwin became one of the most successful commanders of the First Crusade.