Ida, Countess of Hainaut (Ida of Louvain) (died 1139), daughter of Henry II, Count of Louvain, and Adela of Thuringa. Ida was sister to Godfrey I, Count of Louvain.
Ida was married to Baldwin II, Count of Hainaut, who served in the First Crusade with Godfrey of Bouillon. Ida and Baldwin had:
Ida's husband, Baldwin, sold some of his property to the Bishopric of Liège in order to take the cross in the First Crusade. In 1098 he was sent to Constantinople with Hugh of Vermandois after the siege of Antioch, to seek assistance from the Byzantine emperor. He disappeared during a raid by the Seljuk Turks in Anatolia, and was presumably killed.
While on a pilgrimage to Jerusalem in 1106, Ida organized a search for her lost husband in Anatolia but to no avail. Ida’s fate remains unknown.