John II, born 1247, was the oldest son of John I of Avesnes and Adelaide of Holland, daughter of Floris IV, Count of Holland. He became Count of Holland in 1299 with the death of John I, Count of Holland, through his mother Adelaide of Holland, heiress and regent of this county.
He was Count of Hainaut from 1280 to his death and Count of Holland from 1299 until his death. John continued the war between the House of Dampierre and the House of Avesnes against count Guy of Flanders for imperial Flanders. The personal union he established between Hainaut and Holland–Zeeland lasted for another half-century.
He sought help of France against Flanders.
The French defeated the Flemish in 1300 and 1301. The rebels in Zeeland were defeated as well.
John"s brother, Guy of Avesnes, became Bishop of Utrecht. So all his main enemies were gone.
Flemish patriots attacked Hainaut and Zeeland supported by the dissatisfied population there.
Guy of Namur defeated John"s son, William, in a battle on the island of Duiveland. Bishop Guy of Utrecht was taken prisoner. Guy of Namur and Duke John II of Brabant conquered most of Utrecht, Holland, and Zeeland.
Guy of Namur was finally defeated in 1304 by the fleet of Holland and France at the naval Battle of Zierikzee.
John II regained most of his authority when he died in the same year. In 1270, John married Philippa of Luxembourg, daughter of Count Henry V of Luxembourg and Margaret of Bar.
Their children were:
John, Lord of Beaumont, Count of Ostervant. Killed in battle near (11 July 1302).
Henry, a canon in Cambrai, (died 1303).
William I, Count of Hainaut (c 1286 – 7 June 1337) He succeeded his father in 1304. Married Joan of Valois, daughter of Charles, Count of Valois. John of Beaumont (1288 – 11 March 1356).
Margaret (died 18 October 1342), married Robert II of Artois, who was killed at the Battle of the Golden Spurs, 11 July 1302.
Alice or Alix (d 26 October 1317), who married 1290 Roger Bigod, 5th Earl of Norfolk, by whom she had no issue. Isabelle (died 1305), married Raoul de Clermont Lord of Nesle, who was killed in battle at the Battle of the Golden Spurs, 11 July 1302.
Joan, a nun at Fontenelles. Mary of Avesnes (1280–1354), married Louis I, Duke of Bourbon.
Matilda, Abbess of Nivelles.
Willem de Cuser (illegitimate).
