| Noble Family: | House of Dampierre |
| Father: | William II of Dampierre |
| Mother: | Margaret II of Flanders |
| Spouse: | Matilda of Béthune Isabelle of Luxembourg |
| Death Place: | Compiègne |
Guy of Dampierre (French: Gui de Dampierre; Dutch; Flemish: Gwijde van Dampierre) ( - 7 March 1305, Compiègne) was the Count of Flanders (1251–1305) and Marquis of Namur (1264–1305). He was a prisoner of the French when his Flemings defeated the latter at the Battle of the Golden Spurs in 1302.
Guy was the second son of William II of Dampierre and Margaret II of Flanders. The death of his elder brother William in a tournament made him joint Count of Flanders with his mother. (She had made William co-ruler of Flanders in 1246 to ensure that it would go to the Dampierre children of her second marriage, rather than the Avesnes children of her first.) Guy and his mother struggled against the Avesnes (led by John I, Count of Hainaut) in the War of the Succession of Flanders and Hainault, but were defeated in 1253 at the Battle of Walcheren, and Guy was taken prisoner. By the mediation of Louis IX of France, he was ransomed in 1256. Some respite was obtained by the death of John of Hainaut in 1257.
In 1270, Margaret confiscated the wares of English merchants in Flanders for non-payment of customs. This led to a devastating trade war with England, which supplied most of the wool for the Flemish weavers. The dispute was ended by a treaty agreed at Montreuil-sur-Mer on 28 July 1274, effectively abolishing customs charged on English merchants in Flanders. Even after her abdication in 1278, Guy often found himself in difficulties with the fractious commoners.
In 1288, complaints over taxes led Philip IV of France to tighten his control over Flanders. Tension built between Guy and the king; in 1294, Guy arranged a marriage between his daughter Philippa and Edward, Prince of Wales. However, Philip imprisoned Guy and two of his sons, forced him to call off the marriage, and imprisoned Philippa in Paris until her death in 1306. Guy was summoned before the king again in 1296, and the principal cities of Flanders were taken under royal protection until Guy paid an indemnity and surrendered his territories, to hold them at the grace of the king.
After these indignities, Guy attempted to revenge himself on Philip by an alliance with Edward I of England in 1297, to which Philip responded by declaring Flanders annexed to the royal domain. The French under RobertII, count of Artois, defeated the Flemish at the 20 August 1297 Battle of Furnes, and Edward's expedition into Flanders was abortive. Both Philip and Edward had resorted to independently taxing the clergy and Pope Boniface VIII's initial response, the bull Latin: [[Clericis Laicos]], had only led to the outlawing of most English clerics and a French embargo on the export of precious metals and jewels that damaged Boniface's own finances. Under close papal supervision, France and England accepted a 3-year Latin: [[status quo ante bellum|status quo ante]] armistice in October 1297. In 1299, Edward ratified the Treaties of Montreuil and Chartres, betrothing his eldest son to Philip's daughter and himself marrying Philip's sister Margaret. Guy was thus left to his fate when the French invaded again after the end of the armistice in January 1300. He and his son RobertIII were captured by May.
The Flemish burghers, however, found direct French rule to be more oppressive than that of the count. After they smashed a French army at the Battle of the Golden Spurs in 1302, Guy was briefly released by the French who were negotiating terms to end the Siege of Tournai. His subjects, however, refused to compromise. A new French offensive in 1304 destroyed a Flemish fleet at the Battle of Zierikzee and defeated the Flemish at the Battle of Mons-en-Pévèle. Guy was returned to prison, where he died.
Count Guy had two daughters named Margaret by two wives. In June 1246 he married Matilda of Béthune (d. 8 November 1264), daughter of Robert VII, Lord of Bethune, and had the following children:
In March 1265 he married Isabelle of Luxembourg (d. September 1298), daughter of Henry V of Luxembourg, and had the following children: