Waltheof was born around 1098 and died in 1153. He was the son of Simon de Senlis and Maud of Huntingdon. He became Earl of Hungingdon and Northampton when his father died. He fought for King Stephen during the civil war with Empress Matilda.
Family tree for Simon of Huntingdon, son of Simon de Senlis and Maud of Huntingdon showing: