His father, who was descended from an old untitled noble family and possessed a small estate, was by profession an advocate.
As he was intended for the legal profession, he spent some years in attendance on the law classes.
He was urged to take up a pleader's profession; but, like Ovid, he found in letters and gallantry a more congenial pursuit.
Admitted soon after into the counting-house of a friend of his family, he "turned his stool into a Pegasus on three legs, every foot, of course, being a dactyl or a spondee"; but the uncongenial profession affected his health, which was never strong, and he was transferred to the care of his father's relations at Dundee.
Archbishop Ralph of Canterbury refused to consecrate him unless he made a profession of obedience to the southern see; this Thurstan refused and asked the king for permission to go to Rome to consult Pope Paschal II.