Adelaide/Aleid of Holland
Adelaide or Aleide was the daughter of Floris IV, count of Holland and Mathilde of Brabant, whose sister Marie married the emperor Otto IV. Adelaide’s brother William II, count of Holland became Anti-King of the Romans in 1247. Adelaide married John/Jean I of Avesnes, count of Hainaut, in 1246. John was the son of Margaret of Constantinople, countess of Flanders, and her first husband, Bouchard d’Avesnes. When that marriage was dissolved, Margaret rejected the children from it, and made the children of her second marriage to William of Dampierre her heirs in Flanders. The Avesnes and Dampierre chldren fought over their rights and eventually the Avesnes were granted Hainaut, while the Dampierre held Flanders.
Adelaide and John I had seven children: John II, count of Hainaut and Holland, Joanna, abbess of Flines, Bouchard, bishop of Metz, Guy, bishop of Utrecht, William, bishop of Cambrai, Floris, prince of Achaea, and another son, Baldwin.
Adelaide served as regent of Holland for her nephew Floris V after her brother William died, 1258-63, and continued to advise him after he took over. After Floris’s son died, in 1299, Adelaide’s son John II, count of Hainaut, succeeded to Holland as well.
Adelaide, like her mother Mathilde, was a patron of various religious institutions, among them Cistercian houses and beguinages.