Count of Boulogne (c. 1089-1125) and participant in the First Crusade (1096-1099).
Eustace was the eldest son of Eustace II, count of Boulogne, and Ida of Bouillon. He succeeded to his father’s county of Boulogne in northern France; his younger brothers, Godfrey of Bouillon and Baldwin, were to become the first two Frankish rulers of the kingdom of Jerusalem.
Eustace led a contingent of his own in the First Crusade, although it is unclear from the conflicting accounts in the sources whether he traveled to Constantinople with his brothers or with Robert Curthose of Normandy and Robert II of Flanders. However, thereafter he and Godfrey often campaigned together. At the siege of Nicaea (mod. Iznik, Turkey), Eustace helped lead the initial crusader attack, and he aided in the rescue of Bohemund of Taranto’s beleaguered troops at the battle of Dorylaion (July 1097). At Antioch (mod. Antakya, Turkey), he and Godfrey defeated an ambush early in the siege. Later, Eustace, Robert of Normandy, and Adhemar of Le Puy defended the crusader camp while the other leaders attacked the Turkish reinforcements. In the final assault on the city, Eustace led one of the crusader divisions. He participated in the Council of Princes that sought to resolve the conflict between Raymond of Saint-Gilles and Bohemund (November 1098). Shortly thereafter, he assisted Raymond in sacking Ma‘arrat an-Nu’man (December 1098).
In July 1099 Eustace and Tancred successfully raided Nablus. Eustace gained great fame at the capture of Jerusalem (15 July): it was he, Godfrey, and their men who breached the walls of the city while the other crusaders despaired of victory. Shortly after Godfrey’s election, Eustace and Tancred received the surrender of Nablus, and on their return they took an Egyptian scouting party by surprise. At the battle of Ascalon (12 August 1099), Eustace commanded one of the crusader divisions.
Eustace returned home a few months later. On Godfrey’s death, Baldwin I became king of Jerusalem, and when he died in 1118 Eustace was elected as his successor by a group of the magnates of the kingdom. Eustace set off for the Holy Land, but upon his arrival in Apulia a few weeks later, he learned that Baldwin II (of Bourcq) had been crowned king. Without attempting to contest this second election, Eustace returned to Boulogne. Twelfth-century histories and the early crusade epics depict Eustace III as one of the campaign’s heroes. In his epitaph, written at Cluny, he is called “the captor of Jerusalem and the dread of the Eastern empires.”