Margaret was born circa 1145 as the daughter of Thierry, Count of Flanders and Sibylla of Anjou. Her first marriage was to Ralph II, Count of Vermandois, but he suffered from leprosy. Due to this the marriage could not consummated and they separated. He died in 1167 and by 1169 Margaret married her second husband, Baldwin V, Count of Hainaut. They had eight children:
- Isabella of Hainault, married Philip II of France
- Baldwin VI of Hainaut (1171–1205), also count of Flanders and Latin Emperor
- Yolanda of Flanders (1175–1219), married Peter of Courtenay, Latin Emperor
- Philip I, Marquis of Namur (1175–1212)
- Henry of Flanders (1176–1216), Latin Emperor
- Sybille (1179–9 January 1217), married c. 1197 Guichard IV, Sire de Beaujeu (d. 1216). They had a daughter, Agnes of Beaujeu.
- Eustace of Hainaut (d. 1219), regent of the Kingdom of Thessalonica
- Godfrey of Hainaut
Margaret succeeded her childless brother Philip in 1191 as Countess of Flanders, becoming the first woman to succeed to the title. She did not live to enjoy it for very long, dying on 15 November 1194. She was buried in the St. Donatius Cathedral, which was destroyed in 1799.
The foundations of the cathedral were found during the building of a hotel. They were preserved and can be viewed.
As you can see by the coffee cups, the hotel actually uses the basement for events as well. I was told to wait for an hour, before I could go down as they were cleaning up.