Robert I, Count of Flanders

Robert I of Flanders (c. 1035–1093), known as Robert the Frisian, was count of Flanders from 1071 to his death in 1093.

He was the younger son of Baldwin V of Flanders and Adèle of France, a daughter of King Robert II of France. His elder brother, Baldwin, succeeded their father as Baldwin VI, Count of Flanders and his sister Matilda of Flanders had married William the Conqueror, then duke of Normandy and later King of England. His marriage to Gertrude of Saxony, dowager Countess of Holland in 1063 was not arranged by his father but nonetheless agreed to. She was the widow of Floris I, Count of Holland, who already had three children including a daughter Bertha. His nickname 'the Frisian' was obtained, apparently, when he acted as regent for his stepson Dirk V, Count of Holland (Frisia being the name for Holland at the time).

On his deathbed in 1070, Robert's brother Baldwin VI, Count of Flanders, left Flanders to his eldest son Arnulf III and Hainaut to the next oldest son Baldwin with the provision that if either preceded the other in death, he would inherit the other's county as well. Baldwin VI further entrusted his brother Robert with the safeguard of his son Arnulf III, who was still a minor, to which Robert gave his oath of homage and solemn promise to protect his nephew Arnulf. Richilde, Arnulf's mother and de jure Countess of Hainaut was to be regent until Arnulf came of age.

After Baldwin VI's death, however, Robert disputed the succession of Arnulf and entered Ghent with the intent of taking Flanders for himself. Richilde appealed to King Philip I of France who summoned Robert to appear before him. Robert refused and continued his war with Richilde at which point Philip I amassed an army which he brought to Flanders. His army was accompanied by Norman troops, probably sent by Queen Matilda and led by William FitzOsborn. William had an interest in marrying Richilde but he was killed in battle at Cassel, which battle was joined on 22 February 1071. In that engagement Robert's forces were ultimately victorious but Robert himself was captured and his forces in turn captured the Countess Richilde. Both were freed in exchange and the battle continued to its conclusion. Among the dead was Arnulf III, killed by Gerbod the Fleming, 1st Earl of Chester who apparently fought for Robert. As a result of the battle Robert claimed the countship of Flanders. The Countess Richilde and her son Baldwin returned to Hainaut but continued to instigate hostilities against Robert.

Count Robert eventually gained the friendship of King Philip I of France by offering him the hand in marriage of his stepdaughter, Bertha of Holland. As a part of their negotiations Corbie, an important trade center on the border between Flanders and lesser France, was returned to royal control. Unlike his father's reign, under Count Robert, Flanders no longer had peaceful ties to Normandy and became a refuge for the Conqueror's enemies, including his rebellious son, Robert Curthose in 1078. In 1085 Robert the Frisian, along with his son-in-law Canute IV of Denmark, planned a naval attack on England, but after Cnut's assassination the plan was never carried out. Taking a considerable armed escort Robert the Frisian made a pilgrimage to Jerusalem in 1086 and on the return trip home spent time assisting the Byzantine Emperor (Alexios I Komnenos) against the Seljuq Turks. In one battle Robert and three of his companions rode ahead of the main army charging the forces under the command of Kerbogha, whose forces the Christians scattered completely. Robert died 13 October 1093.

Robert married Gertrude of Saxony, widow of Floris I, Count of Holland. They had the following children:

• Robert II, Count of Flanders, married Clementia of Burgundy.
• Adela of Flanders († 1115); married firstly King Canute IV of Denmark, and was the mother of Charles the Good, later Count of Flanders; married secondly Roger Borsa d'Hauteville, Duke of Apulia.
• Gertrude; married firstly Henry III, Count of Leuven and had four children; and secondly Thierry II, Duke of Lorraine, by whom she was the mother of Thierry of Alsace, also later Count of Flanders.
• Philip of Loo, whose illegitimate son William of Ypres was also a claimant to the county of Flanders.
• Ogiva, Abbess of Messines.
• Baldwin († bef. 1080).