Simon was the first known constable of Jerusalem

Officers of the Kingdom of Jerusalem

There were six major officers of the kingdom of Jerusalem: the constable, the marshal, the seneschal, the chamberlain , the butler and the chancellor...

.

He is cited in two royal charters, the first in 1108 and the second in 1115 as Symon ducis filius. He may be identified with the Simontos, mentioned by Anna Comnena as an envoy of Baldwin I of Jerusalem

Baldwin I of Jerusalem

Baldwin I of Jerusalem, formerly Baldwin I of Edessa, born Baldwin of Boulogne , 1058? – 2 April 1118, was one of the leaders of the First Crusade, who became the first Count of Edessa and then the second ruler and first titled King of Jerusalem...

 to Tripoli

Tripoli

Tripoli is the capital and largest city in Libya. It is also known as Western Tripoli , to distinguish it from Tripoli, Lebanon. It is affectionately called The Mermaid of the Mediterranean , describing its turquoise waters and its whitewashed buildings. Tripoli is a Greek name that means "Three...

 in order to receive Greek ambassadors in 1108. She calls him a cousin of the king. Together these imply that he was likely a son of Henry, Duke of Lower Lorraine

Henry, Duke of Lower Lorraine

Henry I was the count of Limburg and Arlon from 1082 to his death and duke of Lower Lorraine between 1101 to 1106. He was the son of Waleran I of Limburg and Jutta, daughter of Frederick, Duke of Lower Lorraine....

, a great-grandson of Eustace I of Boulogne

Eustace I of Boulogne

Eustace I, count of Boulogne, was a son of Count Baldwin II of Boulogne and Adelina of Holland. He held the county from 1046 until his death in 1049.-Family and children:...

by his maternal grandmother.