614年,贾斯图斯出席了法兰克人之王克洛泰尔二世举办的巴黎教会会议[21]。贾斯图斯和地处于坎特伯雷的圣彼得和保罗修道院(之后更名为圣奥古斯丁修道院)院长彼得一同出席会议的原因尚无定论[4]。有可能只是巧合,但历史学家詹姆斯·坎贝尔(James Campbell)曾认为,克洛泰尔召见不列颠神职人员的目的是为了在宗教权威上胜过肯特王国[22]。历史学家N·J·海厄姆(N. J. Higham)提供了另一种解释,他认为法兰克针对肯特王国的政策变化是埃塞尔伯特派几位主教前往参加会议的主要原因,因为这些变化对肯特的独立构成威胁,国王派两位神职人员前往巴黎,以期与克洛泰尔通过谈判达成妥协[3]:116。
624年,贾斯图斯成为坎特伯雷大主教[24],教宗波尼法爵五世授予他披带这一大主教管辖权的象征,贾斯图斯随后将罗曼努斯晋牧为新的罗切斯特主教[4]。波尼法爵五世还给了贾斯图斯一封信,祝贺他成功令国王“阿杜尔沃尔德”(Aduluald,可能指的是肯特君主埃德博尔德)皈依基督教,比德的《英吉利教会史》中就包含有这封信的内容[25]:31-32。比德认为埃德博尔德皈依是贾斯图斯的前任坎特伯雷大主教劳伦斯说服的,但历史学家D·P·科比(D. P. Kirby)认为,教宗的祝贺信说明这更可能是贾斯图斯的功劳[25]:33。包括芭芭拉·约克和亨利·迈尔-哈廷在内的其他多名历史学家则认同比德的结论,埃德博尔德是在劳伦斯任内皈依的[11]:75-76。约克认为,埃德博尔德统治时期肯特共有两位君主,另一位埃塞尔沃尔德(Æthelwald)才是教宗贺信里所说的“阿杜尔沃尔德”。约克还进一步认为,贾斯图斯在埃塞尔伯特去世后令埃塞尔沃尔德也皈依了基督教[26]。
^ 3.03.13.23.3Higham, N. J. The Convert Kings: Power and Religious Affiliation in Early Anglo-Saxon England. Manchester, UK: Manchester University Press. 1997. ISBN 0-7190-4827-3.
^Bede. A History of the English Church and People. Translated by Leo Sherley-Price. New York: Penguin Classics. 1988: 85–86. ISBN 0-14-044042-9.
^ 11.011.1Mayr-Harting, Henry. The Coming of Christianity to Anglo-Saxon England. University Park, PA: Pennsylvania State University Press. 1991. ISBN 0-271-00769-9.
^Colgrave, Bertram. Introduction. The Earliest Life of Gregory the Great Paperback reissue of 1968. Cambridge, UK: Cambridge University Press: 27–28. 2007. ISBN 978-0-521-31384-1.
^Brooks, Nicholas. The Early History of the Church of Canterbury: Christ Church from 597 to 1066. London: Leicester University Press. 1984: 221. ISBN 0-7185-0041-5.
^ 15.015.1Brooks, Nicholas. From British to English Christianity: Deconstructing Bede's Interpretation of the Conversion. Howe, Nicholas; Karkov, Catherine (编). Conversion and Colonization in Anglo-Saxon England. Tempe, AZ: Arizona Center for Medieval and Renaissance Studies: 24–27. 2006. ISBN 0-86698-363-5.
^Campbell, A. (编). Charters of Rochester. Anglo-Saxon Charters 1. London: British Academy/ Oxford University Press. 1973: c. ISBN 0-19-725936-7.
^ 19.019.1Morris, John. Arthurian Sources, Vol. 2: Annals and Charters. Arthurian Period Sources. Chichester, UK: Phillimore. 1995. ISBN 0-85033-757-7.
^ 20.020.120.2Levison, Wilhelm. England and the Continent in the Eighth Century: The Ford Lectures Delivered in the University of Oxford, 1943. Oxford, UK: Clarendon Press. 1946: 223–225. ISBN 0-19-821232-1.
^Campbell, James. The First Century of Christianity in England. Essays in Anglo-Saxon History. London: Hambledon Press: 56. ISBN 0-907628-32-X.
^Lapidge, Michael. Mellitus. Lapidge, Michael; Blair, John; Keynes, Simon; Scragg, Donald (编). The Blackwell Encyclopaedia of Anglo-Saxon England. Malden, MA: Blackwell Publishing: 305–306. 2001. ISBN 978-0-631-22492-1.
^ 24.024.1Fryde, E. B.; Greenway, D. E.; Porter, S.; Roy, I. Handbook of British Chronology Third revised. Cambridge, UK: Cambridge University Press. 1996: 213. ISBN 0-521-56350-X.