EUSTACHE [I] de Boulogne (-[1049]). Comte de Boulogne. Malbodus, abbatus" records donations to the abbey of Saint-Amand by charter dated to [1061] including "villam…Lurcium" held "ex comite Balduino" by "Eustachius comes et quidam miles Rainerus"[574].It is possible, but not certain, that this charter refers to Eustache [I]. "Karolus…comes Flandrie" confirmed property of the abbey of Marchiennes at Lille by charter dated 1125 which names "comes Balduinus proavus meus…coniuge sua comitissa Adela, et…baronibus suis Eustachio…comite Bolonie, Rogero comite de Sancto Paulo"[575], presumably referring to Baudouin V Count of Flanders and so dated to between 1035 and 1067, in which case the document could refer either to Eustache [I] or Eustache [II]. m MATHILDE de Louvain, daughter of LAMBERT I "le Barbu" Comte de Louvain & his wife Gerberge de Lorraine [Carolingian] ([990/1000]-). The Genealogica comitum Buloniensium records that "Henricum seniorem de Bursella [=filius Ermengardis]" was father of "Lambertum comitem et Henricum fratrem eius et Mathildem sororem eorum", specifying that Mathilde married "comes Eustachius de Bolonia"[576], but this appears to be a confused representation of the situation. The primary source which confirms that Mathilde was the daughter of Comte Lambert [I] has not yet been identified but this is compatible with the chronology. Her birth date range is estimated from the estimated date of her parents' marriage and the likely birth date of her eldest son in [1015/20]. This shows that it is chronologically impossible for Mathilde's father to have been the son of Ermengardis of Lower Lotharingia. Comte Eustache [I] & his wife had five children