Adam reported to the exchequer in 1164, his father John being then alive, for about twenty-four knights' fees in Herefordshire (Liber Niger de Scaccario, i.
151), said to be the fief of Sibilla, daughter and heiress of Bernard of Neufmarché, and widow of Miles, earl of Hereford (Stapleton, Magni Rotuli Scaccarii Normanniæ, i. Observations clxi).
He made his peace with the king in 1180, submitting to a fine of a thousand marks, and receiving back his paternal lands, together with those that he held in Normandy in right of his second wife, Mabil; the lands that he had held in Herefordshire remained forfeited, and were described as ‘feodum Adæ de Port fugitivi;’ they appear to have passed to William de Braose in right of his mother Bertha, a daughter of Sibilla by Miles of Gloucester, for in 1194 he paid 22l.
Of Adam's fine two hundred and fifty-one marks remained unpaid at the accession of Richard I (Pipe Roll, 1189–90, p. 199).
William Dugdale has a story that early in John's reign he was accused of causing the death of Henry II, and fled the country.
This strange story, derived by Dugdale from a Cottonian manuscript, to which no reference is given, seems to have arisen from a misunderstanding of the passage relating his outlawry in 1172 (‘calumniatus de morte … regis;’ Gesta Henrici II which is in two Cottonian manuscripts), and from the description of the lands in Herefordshire that he had lost (see above).
In 1202 he fined ten marks and a palfrey in respect of a division of land in Hampshire with the abbot of Abingdon (Rotuli de Oblatis, p. 183).
He was warden of Southampton Castle in 1213, and died in or about that year, when his eldest son had livery of his lands in Hampshire and Berkshire (Rotuli de Oblatis, p. 477).
135; Round, Geoffrey de Mandeville, p. 233); but the husband of Sibilla was, he himself states in the Sherborne charter, the grandson of Henry.
By 1180 Adam married Mabil, daughter of Reginald d'Orval or Aurevalle, and his wife Muriel, daughter of Roger St. John, to whom Mabil appears eventually to have become heiress, and in her right he in that year held the honour of Lithaire and Orval in the vicomté of Coutances (Stapleton); by her he had issue, his son and heir being William, who assumed the name of St. John (Monasticon, u.s.).