[1] He secured the personal union between the counties of Flanders and Hainaut and maintained close links to the Anglo-Saxon monarchy, which was overthrown by his son-in-law, William the Conqueror, near the end of his life.

Baldwin married Adela, daughter of King Robert II of France, in 1028 in Amiens;[2] at her instigation he rebelled against his father but in 1030 peace was sworn and the old count continued to rule until his death.

She dispensed generously to the poor, making contact with the monastery of Saint Bertin at St Omer, and received her son King Harthacnut of England at Bruges in 1039.

[5] As count of Flanders, Baldwin supported the king of France in most affairs, but he was also father-in-law to Duke William II of Normandy, who had married his daughter Matilda.

Flanders played a pivotal role in Edward the Confessor's foreign policy when the king of England was struggling to find an heir.