Family
 Sibylla d'AnjouDaughter of Fulk V d'Anjou, Count of Anjou, King of Jerusalem and Eremburge de la Fleche, Countess of Maine. Born ± 1112 Died 1165, approximately 53 years Married/ Related to:  Theodoric of Alsace, Count of Flanders 1) 2) 3)Born ± 1099 Died 17 Jan 1167/68, approximately 68 years Notes: Claimed the county of Flanders through his descent from Robert, via a daughter of his. Succeeded by his sons Baldwin and Philip. Children: 2. Matthew of Alsace, Count of Boulogne 3)Born ± 1137 Died 25 Dec 1173 Killed in battle at Driencourt, approximately 36 years Notes: "Cumque defecissent in Bolonia legitimi heredes, matheus filius Theoderici comitis Flandrensis, licet illicite, duxit abbatissam, et suscitavit semen hereditarium duas filiam generando, et remisit eam ad locum suum." (Genealogia comitum Bulonensium) Matthew abducted his wife, the nun Marie, and had two daughters with her - and also claiming the title of Count of Boulogne in his own right. | |||
Sources
1) Source: Genealogia comitum Flandrensium ex libro Florido et Chronico Aldenburgensi, etc "Cui succesit balduinus comes hanonie, nepos ejus, postea constantinopolitanus imperator et duxit filiam comitis campanie, nomine Mariam, ex qua genuit duas filias Johannam et Margaretam." (Questionable reliability of evidence)2) Source: Genealogia comitum Flandrensium ex libro Florido et Chronico Aldenburgensi, etc "cui successit Magareta soror ejus, uxor comitis Balduini Hannonie; obiit anno Domini M C XCIIII et in ecclesia sancti Donatiani sepeliture". This is following Philip, described as son of Theoderic (Data from secondary evidence)
3) Source: Genealogia comitum Bulonensium A short genealogy connecting the early Merovingians to the later counts of Boulogne, written circa the 11th century. The earliest generations are almost certainly fictional. Considered a reliable secondary source for generations from Arnulf of Metz onwards. Considered a "primary" source for events from the year 1000 onwards.. External Link
https://www.dmgh.de/mgh_ss_9/index.htm#page/300/ (Data from direct source)
4) Source: Chronica Magistri Rogeri de Houdene "After Easter, Philip, king of France, took to wife the daughter of the earl of Hainault, and niece of Philip, earl of Flanders, being the daughter of his sister" (Data from secondary evidence)