Anselm Marshal (died 23 December 1245) was the youngest and last of the five sons of William Marshal. Had he lived longer, he would have become Earl of Pembroke and Earl Marshal upon the death of his brother Walter on 24 November 1245. Since he only survived his brother a month, he was never confirmed in the earldom. He died at Chepstow Castle and was buried in Tintern Abbey.
When William Marshal was composing his will in 1219, he originally intended to allot nothing to his youngest son, Anselm, who was named after William's younger brother. It has been suspected that he wished for the young Anselm to rise from low rank to high on his own merits as William himself had done as a young knight errant. His advisors, however, convinced the ailing Marshal to grant Anselm a small piece of land.
Anselm was married to Maud, the daughter of Humphrey de Bohun, Earl of Hereford and Essex. They had no children and Anselm's estates were divided between his four surviving sisters, Isabel, Sibyl, Eva, and Joan, and their husbands. The earldom of Pembroke lay vacant until 1247, when it was recreated for William de Valence, husband of Joan de Munchensi, heiress of Anselm's sister Joan and her husband Warin de Munchensi.
The remarkable extinction of the male line of the Marshall family was credited to a curse bestowed upon the family in 1218 by Bishop of Ferns, Ailbe Ua Maíl Mhuaidh (died 1223). Each of the five sons of William Marshal, 1st Earl of Pembroke successively inherited the title, but, as Ua Maíl Mhuaidh predicted, none had children and the male line of the family died out.
- Painter, Sidney. William Marshal: Knight-Errant, Baron, and Regent of England. Toronto: University of Toronto Press, 1982.