Ernulf was held in repute as an authority on canon law, and was consulted on various nice points by Bishop Walkelin of Winchester, to whom he addressed a ‘Tomellus sive Epistola de Incestis Coniugiis.’ The date of this treatise is between 1089 (since it mentions Lanfranc as dead) and 1098 (when Walkelin himself died). It is printed in Luc d'Achery's ‘Spicilegium,’ iii. 464–70 (ed. L. de la Barre, 1723), where it is wrongly dated 1115, and in Migne's ‘Patrologiæ Cursus Compl.’ ser. Lat. clxiii. p. 1457. Another letter, written chiefly on the sacramental controversy, to Lambert, abbot of St. Bertin (‘Epistola solutiones quasdam continens ad varias Lamberti abbatis Bertiniani quæstiones, præcipue de corpore et sanguine Domini,’ printed in L. d'Achery, ubi supra, iii. 470–4), probably belongs to the same period of Ernulf's life. It was composed in or after 1095. A beautiful manuscript, written in the early part of the twelfth century, once forming part of the library of St. Albans Abbey, and now preserved at Oxford (Cod. Bodl. 569), contains the work in immediate association with the kindred treatises of Archbishop Guitmund of Aversa, of Lanfranc, and of Anselm. Testimony to the affection with which Ernulf was regarded by his neighbours at Canterbury may be found in two poems addressed to him by Raginald, monk of St. Augustine's, and recently printed by Dr. Liebermann (Neues Archiv der Gesellschaft für ältere deutsche Geschichtskunde, 1888, xiii. 537, et seq.)
In 1107, through the influence of Anselm, Ernulf was promoted to the important abbacy of Peterborough, where his rule was remembered not only by his businesslike activity, but also by his personal saintliness and mild and gracious bearing. His popularity had its witness in the increased number of the monks. At Peterborough, as at Canterbury, he built considerable additions, but these were destroyed by fire; and he was just planning a new building when he was called to the see of Rochester, on the advancement of its bishop, Ralph, to that of Canterbury in 1114. King Henry, says the ‘Peterborough Chronicle,’ was on his way to the continent when he was detained at Burne (Eastbourne) by stress of weather. While waiting there he sent for the abbot of Peterborough to come to him in haste, and on his arrival urged him to accept the bishopric of Rochester. The suggestion was Archbishop Ralph's (Eadmer, Hist. Nov. p. 225; Gervase of Canterbury, Op. Hist. ii. 377), and was supported by the prelates and barons present, but Ernulf long withstood. The king then ordered the archbishop to lead him to Canterbury and there bless him to bishop, ‘wolde he, nolde he;’ and thus it seems Ernulf was constrained to yield 19 Sept. 1114. But the monks of Peterborough were sorry, for that he was a very good and meek man, and did full well for his monastery, both within and without.
The statement (Le Neve, Fasti Eccl. Angl. ii. 558, ed. Hardy) that Florence of Worcester (Chron. ii. 67, ed. B. Thorpe, 1849) and Symeon of Durham (Hist. Reg., ad an., ii. 248, ed. T. Arnold, 1885) date Ernulf's election as bishop on 15 Aug. rests on an apparent misreading of the text. He was invested at Canterbury 28 Sept., installed at Rochester 10 Oct. (Eadmer, l. c.), and consecrated at Canterbury in company with Geoffrey, bishop of Hereford, 26 Dec. (ib. p. 236). Of his pontifical career little is related beyond his assistance at consecrations of other bishops. The confidence which he still enjoyed among the monks of Canterbury is shown by the appeal they made to him in 1123 to support their protest against the appointment of any one but a monk to be their archbishop (Gervase of Canterbury, ii. 380). But Ernulf was already declining in health, and died not long after (15 March 1124), being eighty-four years of age.
Besides the two letters already mentioned Ernulf was the author of a great collection of documents relating to the church of Rochester, English laws (from Æthelberht onwards), papal decrees, and other materials for English and ecclesiastical history. This famous work, known as the ‘Textus Roffensis,’ is preserved among the muniments of Rochester Cathedral. Extracts were printed by Wharton, ‘Anglia Sacra,’ i. 329–40 (1691), and Wilkins, ‘Leges Anglo-Saxonicæ’ (1721); and the whole was published by Thomas Hearne in 1720.
[William of Malmesbury's Gesta Pontificum Anglorum, p. 137 et seq. (ed. N. E. S. A. Hamilton, 1870), and the Peterborough Chronicle (Anglo-Saxon Chronicles, i. 370, cf. 374, ed. B. Thorpe, 1861). There is a letter probably written to him by St. Anselm (‘Clarissimo Arnulfo frater Anselmus salutem,’ &c., ep. xxx. Op. p. 322 et seq., 2nd ed. Gerberon, 1721); and references in epp. lv. (p. 331) and lxv. (p. 336). See also Eadmer's Hist. Nov. pp. 291, 294, ed. M. Rule; Gervase of Canterbury's Oper. Hist. ii. 294, ed. W. Stubbs, besides the places cited in the text. C. E. du Boulay's Hist. Univ. Paris, i. 432, confounds our Ernulf with an earlier chanter of Chartres, a disciple of Fulbert, bishop of that see (d. 1029), while Bale's Scriptt. Brit. Cat. ii. 70, pp. 184 et seq., seems to mix him up with the famous Arnold of Brescia. Cf. Gunton's Hist. of the Church of Peterborough, pp. 20–1 (1686).]
