Alice FitzRoy was the illegitimate daughter of King Henry I of England

Henry I of England

Henry I was the fourth son of William I of England. He succeeded his elder brother William II as King of England in 1100 and defeated his eldest brother, Robert Curthose, to become Duke of Normandy in 1106...

 by one of his many mistresses. She was married to Matthieu I of Montmorency

Matthieu I of Montmorency

Matthieu Ier de Montmorency was lord of Montmorency, of Écouenof Marly-le-Roi, in Conflans-Sainte-Honorine and Attichy. He was also Constable of France from 1138 to 1160 under Louis VII....

, the eldest son of Bouchard IV de Montmorency and Agnes de Beaumont-sur-Oise, lady of Conflans-Sainte-Honorine in 1126 and had the following issue:

1. Henry, died young before 1160
2. Bouchard V de Montmorency,(d. 1189 in Jerusalem), who married in 1173 Laurette of Hainaut (d. 9 August 1181), daughter of Count Baldwin IV of Hainaut. They had a son Matthieu II de Montmorency, nicknamed the Great.
3. Theobald de Montmorency, seigneur de Marly, he went on crusade in 1173. He ended his life as a monk of Citeaux in 1190.
4. Herve de Montmorency, abbot of Saint-Martin de Montmorency, then deacon of the Church and dean of Paris nd dies in 1192.
5. Matthieu de Montmorency (d.Constantinople 1204), he inherited the lordship from his brother Theobald and married Mathilde de Garlande (d.1224) had issue.

Alice died before 1141 when her husband married his second wife Adelaide of Maurienne, the widow of Louis VI of France

Louis VI of France

Louis VI , called the Fat , was King of France from 1108 until his death . Chronicles called him "roi de Saint-Denis".-Reign:...

.

Matthieu also has a daughter however it is uncertain which wife was her mother:

1. Alice; m.Gasce de Poissy (d.1189)