Gaston IV of Bearn

Gaston IV (died 1131) was viscount of Béarn from 1090 to 1131. He was called "le Croisé" ("the Crusader") due to his participation in the First Crusade as part of the army of Raymond of Saint-Gilles.

Gaston succeeded his father Centulle V in 1090. During his rule, the borders of Béarn were established more definitively; he defeated the viscount of Dax, and took control of Orthez, Mixe, and Ostabaret by 1105. He also gained Montaner through his marriage to Talesa, daughter of Sancho Ramírez, Count of Ribagorza and lord of Aibar and Javierrelatre, illegitimate half-brother of King Sancho Ramírez and son of Ramiro I of Aragon. Though technically a vassal of the Duchy of Aquitaine, ruled at that time by William IX, Gaston effectively made Béarn an autonomous territory.

Before becoming viscount, Gaston had fought in the Reconquista in Spain, and he led a Béarnais contingent on crusade under Raymond IV of Toulouse in 1096. He was one of the lesser knights, but he carried his own standard and commanded his own men. At the siege of Antioch he led one of the divisions in the final battle against Kerbogha. During the power struggle following the capture of Antioch, Gaston deserted Raymond for Godfrey of Bouillon and marched with him to Jerusalem. Gaston and Tancred were sent ahead of the main army to occupy Bethlehem, and during the siege of Jerusalem, Gaston was in charge of Godfrey's siege engines. On July 15, 1099, Gaston was the first crusader to enter the city.

...
Wikipedia