House of Flanders

House of Flanders
Arms of the County of Flanders
Country	France  Holy Roman Empire  Jerusalem Latin Empire
Founded	863
Founder	Baldwin Iron Arm
Final ruler	Jerusalem: Baldwin I Boulogne: Matilda I Flanders: Margaret II
Titles	Latin Emperor of Constantinople King of Jerusalem Defender of the Holy Sepulchre Duke of Lower Lorraine Margrave of Flanders Margrave of Namur Count of Flanders Count of Hainaut Count of Edessa Count of Boulogne Count of Namur Lord of Bouillon
Estate(s)	Flanders, Hainaut, Constantinople, Boulogne
Dissolution	10 February 1280
Cadet branches	House of Hainaut House of Boulogne House of Mons

The House of Flanders, also called the Baldwins (Latin: Balduini, French: Baudouinides), was a medieval ruling family of Frankish origin that was founded by Baldwin Iron Arm, son-in-law of Charles the Bald. The House of Flanders was the first dynasty to transform a county function of the Carolingian Empire into a hereditary fiefdom, the County of Flanders, falling under West Francia, created by the Treaty of Verdun in 843.^[1]

From 1051, the House of Flanders also reigned over the County of Hainaut, with Baldwin I of Hainaut. In 1119, on the death of Baldwin VII, the family had a series of setbacks, but in 1191, the family recovered the title of Count of Flanders with Baldwin VIII (Baldwin V of Hainaut).

The dynasty established the Latin Empire of Constantinople during the Fourth Crusade, and it also briefly ruled the County of Namur (1188–1212). The House of Flanders became extinct in 1280 with the death of Margaret II.

A cadet branch, the House of Boulogne, ruled over the County of Boulogne. Members of this house joined the First Crusade, established the Kingdom of Jerusalem, and produced its first kings.