Simon de Senlis III, 8th Earl of Huntingdon, 5th Earl of Northampdon

The addition of "St." before Senlis is a mystery. Wikipedia shows a commune called Senlis, which was not called Saint-Senlis. Perhaps the addition of "St." relates to the abbey St Vincent, which Queen Anne of Kiev founded in at Senlis in 1065.

FMG England, Earls Created 1067-1122 (updated 9 Mar 2022) Earls of Huntingdon

(FYI: Simon III de Senlis and Alice de Gaunt (Gand) had two children: Simon and Gunnor.)

Earl Simon (d. Aug 1153) and his wife Isabelle de Beaumont (d. aft. after 1188) had four children:

1. SIMON de Senlis ([1138]-Jun 1184, bur St Andrew's Priory).
The Vita et Passio Waldevi Comitis names “Simonem de Senliz tercium et duas filias…Amicia et Hawisia” as the children of “comes…Simon…[et] Ysabellam comitissam, filiam Roberti comitis Leicestrie”[606].
Robert of Torigny records that "Symon filius eius" succeeded on the death in 1153 of "Symone comite Huntedoniæ"[607].
He was recognised as Earl of Huntingdon and Northampton in 1174. “Simon comes de Norhamtonia” donated property to Ramsey Abbey, Huntingdonshire by charter dated 28 Mar 1175, witnessed by “Simon fratre comitis…”[608].
m ALICE de Gand, daughter of GILBERT de Gand Earl of Lincoln & his wife Rohese de Clare (-1238, bur Bridlington).
Robert of Torigny records that "filiam eius unicam [Gisleberti de Gant]" married "Symon iuvenis filius comitis Symonis"[609]. The Stemma fundatoris of Bardney Abbey names “Aliciam” as the daughter of ”Gilbertus”, adding that she married “Simon de Monteforti comes Noramtoniæ”[610].
A manuscript genealogy of the Gant family names “Aliciam” as the daughter of “Gilbertus”, adding that she married “Simoni de sancto Licio, comiti Huntingtoniæ et Northamptoniæ”, died childless, and was buried “apud Bredlinton”[611].
"A. comitissa Norhamtunie filia Gilleberti comes Lincolnie" confirmed the donation of land in Scampton to Kirkstead abbey by "Radulfus filius Gilleberti", for the health of "sponsi mei Simonis comitis", by charter dated to early in the reign of King Henry II[612].
Simon & his wife had two children:

a) GUNNOR. The Stemma fundatoris of Bardney Abbey names “Gonorram” as the daughter of “Simon de Monteforti comes Noramtoniæ” and his wife Alice, adding that she died without heirs[613].
b) [614]SIMON de Senlis (-young). “Simon de sancto Licio frater comitis Symonis” donated property to the Abbey of de la Pre, Northamptonshire, for the soul of “Symonis nepotis mei”, by undated charter witnessed by “comitissa Adelyz de Gaund…”[615].

2. AMICE de Senlis....
3. HAWISE de Senlis....
4. ISABELLE de Senlis
Earl Simon had one [probably illegitimate] son [by an unknown mistress]:
5. SIMON de Senlis (-after 28 Mar 1175). “Simon comes de Norhamtonia” donated property to Ramsey Abbey, Huntingdonshire by charter dated 28 Mar 1175, witnessed by “Simon fratre comitis…”[619]. “Simon de sancto Licio frater comitis Symonis” donated property to the Abbey of De la Pre, Northamptonshire, for the soul of “Symonis nepotis mei”, by undated charter witnessed by “comitissa Adelyz de Gaund…”[620]. It is assumed that Simon was illegitimate, which appears to be the most likely explanation for his having the same name as his brother.