The 'Historia Regum Britanniae' of Geoffrey, archdeacon of Mon-mouth and later bishop of st. Asaph (1152-84), here with only the first prologue addressed to Robert earl of Gloucester: beg. 'Cum mecum multa et de multis sepius animo reuoluens': text beg. 'Britannia insularum optima' (fol. 1). A 13th-cent. hand, which has added the title 'Liber Bruti, et continet quater viginti et x folia, et cc et v capitula' (fol. 1), has inserted marginalia and some rough sketches throughout. On…