King Henry I of England (r.1100-1135) holds the record for an English monarch with the most acknowledged illegitimate children. He is estimated to have had between 20 and 25 illegitimate children, most of them daughters. Unfortunately, not much is written of these daughters. The chroniclers seemed to care more about his illegitimate sons, especially Robert, Earl of Gloucester, said to be Henry’s oldest and favourite illegitimate child. The birth years of his illegitimate children are uncertain, as is their birth order. Henry had various mistresses, but not much is known of any of them. For many of his illegitimate children, their mothers are unknown.

Henry had nine illegitimate sons that he recognised as his own. The number of daughters is less certain. There are several daughters, such as Sybilla, Queen of Scotland, Matilda, Countess of Perche, and Juliana, who are known for sure to have belonged to Henry. There are some that we know of, only because of charters they were mentioned in, such as Adeliza. There is one probable daughter, whose name was not recorded, but there is significant evidence that she was the wife of the Scottish lord, Fergus of Galloway. There is also Rohese, a daughter of Henry’s mistress, Sybilla Corbet, but whether she was Henry’s or not is less certain. There is Sybil of Falaise, who was recorded as being a relative of the king, but the exact relationship is unknown. Then there is Emma, who is speculated to be Henry’s daughter, but there is no hard evidence for this.

Henry’s only legitimate daughter was the famous Empress Matilda. Interestingly enough, Henry had three illegitimate daughters named Matilda! Also a fourth one, Constance is sometimes called Matilda. I have made a list of Henry’s illegitimate daughters using various web sources. There is no particular order, but his confirmed daughters are named first.

1. Sybilla of Normandy (died 13 July 1122), married King Alexander I of Scotland around 1107 and had no children. She was the only one of Henry’s illegitimate daughters to marry a king. She is often said to be a daughter of Sybilla Corbet, but this is uncertain. Sybilla appears to be one of Henry’s older children, born in the early 1090s, probably before Henry began his affair with Sybilla Corbet. Even though Sybilla and Alexander had no children, they appear to have been a devoted couple. Sybilla was of noteworthy piety, and after her death, Alexander planned to dedicate a priory to her memory.

2. Matilda married Duke Conan III of Brittany before 1113 and had three children. The identity of Matilda’s mother is unknown. Conan disinherited their only son on his deathbed, saying that he was not actually his father. The reason for this remains mysterious, and there’s nothing to indicate that Matilda was guilty of adultery.

3. Matilda (died 25 November 1120), married Count Rotrou III of Perche in 1103 and had two daughters. Her mother’s name was Edith, but nothing is known about her origins. Matilda drowned with her legitimate brother, William on the White Ship. William was initially rescued from the shipwreck and was being rowed to shore on a lifeboat. However, he heard Matilda’s cries for help, so he ordered for the boat to be rowed back to the wreck. The small boat was swamped by other victims of the wreck, desperately trying to climb in it, causing it to break apart.

4. Juliana, married Eustace de Breteuil, in 1103, who was also of illegitimate birth and had two daughters. Her mother was possibly a mistress named Ansfride, who bore Henry two sons, Richard (who drowned on the White Ship), and Fulk, who became a monk. Juliana was one of Henry’s older children. She became a central figure in a rebellion against her father. In 1119, a dispute erupted between Juliana’s husband and Ralph Harnec, about Ralph’s castle of Ivry. To make peace, King Henry organised a hostage exchange between Eustace and Ralph. Eustace received Ralph’s son, while Ralph received Eustace and Juliana’s two daughters. Eustace had Ralph’s son blinded. Furious, Ralph had Juliana’s two daughters blinded, and their noses cut off. He did this with Henry’s own permission. Greatly angered, Juliana defended her husband’s castle of Breteuil against her father. Henry besieged the castle, and Juliana tried to kill him with a crossbow but missed. Henry had her locked in the castle, but she escaped by jumping into the moat. Eustace and Juliana eventually submitted to Henry. After her husband’s death in 1136, Juliana became a nun at Fontevrault Abbey.

5. Constance (sometimes called Matilda), married Roscelin, Viscount of Beaumont-sur-Sarthe, and had four children. The identity of Constance’s mother is unknown.

6. Mabel (sometimes called Eustacie), married William III Gouet, Lord of Montmirail, and had one son. The identity of Mabel’s mother is unknown.

7. Alice (Aline, Alix) (died before 1141) married Matthew I of Montmorency in 1126 and had six children. The identity of Alice’s mother is unknown.

8. Matilda, Abbess of Montvilliers. The identity of Matilda’s mother is unknown. She supported her legitimate sister, Empress Matilda.

9. Isabel, her mother was Isabella de Beaumont, daughter of Robert de Beaumont, Earl of Leicester, and Isabel de Vermandois. Isabel was probably the youngest of Henry’s children, born in the 1120s. She witnessed two charters with her mother but never married.

10. Adeliza, her mother was a noblewoman, Edith Fitzforne. Adeliza had one full-brother, Robert, Lord of Okehampton, who she appeared in charters with. Nothing else is known about her.

11. Possibly Gundred, a daughter of Henry’s long-time mistress, Sybilla Corbet. It’s uncertain if her father was Henry, or Herbert FitzHerbert, who Sybilla later married.

12. Possibly Rohese, married Henry de la Pomerai. She was a daughter of Sybilla Corbet. It is uncertain whether her father was Henry, or Herbert FitzHerbert, who Sybilla later married.

13. Probably an unnamed daughter, who married Fergus, Lord of Galloway, and had three children. Some sources call her ‘Elizabeth’ or ‘Joan’, but there is no contemporary source for her name. This marriage is hinted by the fact that documents mention Fergus’ children and grandchildren being related to the English monarchs of the time.

14. Possibly Emma, who married Guy IV of Laval. This is based on a tomb inscription, which names her as a daughter of a king. However, the is no other evidence to connect this Emma to Henry I. Her daughter-in-law, also named Emma was a daughter of Reginald, Earl of Cornwall, one of Henry’s illegitimate sons, so this seems unlikely. It is possible that the elder Emma was confused with her daughter-in-law.

15. Possibly Sybil of Falaise, married Baldwin de Boullers. She is described as a kinswoman or niece of Henry I. She possibly could have been the daughter of Henry’s brother, Robert, Duke of Normandy instead.

There possibly could have been other daughters, such as an unnamed one who was the second wife of Helie de Saint-Saens, a Norman lord. The first wife of Helie de Saint-Saens’s was an unnamed illegitimate daughter of Henry’s brother, Robert, Duke of Normandy. It is uncertain if Helie married twice, so this daughter’s existence is uncertain. King Henry also had an unnamed daughter who was betrothed briefly to William de Warenne. The betrothal was broken off due to consanguinity. This unnamed daughter possibly could have been one of Henry’s above-named daughters, but there is no evidence for this.

Most of the marriages of Henry’s illegitimate daughters were to lords along the Norman border. Some of them were married to very powerful lords who ruled over large areas, such as the Duke of Brittany. Others married more minor lords. All of these marriages were probably arranged by Henry to cement alliances with his neighbours. It appears that these lords did not care about their wives’ illegitimacy, but what was important about their marriages is the fact that it linked them to the king.