Agnes Poitou of Aquitaine was born after 1060 to William VII of Aquitaine (1023-1058) and Ermesinde and died circa 1078 of unspecified causes. She married Peter I de Savoie (c1048-1078) . Charlemagne (747-814)/s, Rollo of Normandy (860-932)/s.
|Offspring of Agnes Poitou and Peter I de Savoie (c1048-1078)|
|Alix de Savoie (c1076-1111)||1076||1111||Boniface del Vasto (1060-c1131)|
|Agnes de Savoie (c1077-1091)||1077||1091||Frédéric de Montbéliard (c1050-1092)|
|Berta de Savoie (1075-1111)||1075||1111||Peter I of Aragon and Navarre (c1068-1104)|
Note the confusion on Wikipedia about her daughters. There are three daughters (Alix, Agnes, Berta) in Catalan and Italian ; two (Alix, Agnes) in German  and Dutch ; one (Alix) in English, Spanish, and French ; and another one (Agnes) in Piemonteis.
Berta would have married Peter I of Aragon, and died childless..
Alix and Agnes married Frederick (Montbeliard, Luxembourg, Susa), son of Sophie de Bar (c1018-1093), and Boniface (Vasto, Saluzzo, Savone), but it is not clear who married whom.