Petro III wa Aleksandria (alifariki 11 Novemba 489) kuanzia mwaka 477 hadi kifo chake alikuwa Patriarki wa Aleksandria (Misri) na Papa wa 27 wa Kanisa la Wakopti ambalo linamheshimu kama mtakatifu. Sikukuu yake huadhimishwa tarehe ya kifo chake. Maandishi yake hayajatufika. Watakatifu wa Agano la Kale Orodha ya Watakatifu Wakristo Orodha ya Watakatifu wa Afrika Orodha ya Watakatifu Wafransisko Petros III, Mongos (482–490). Official web site of the Greek Orthodox Patriarchate of Alexandria and All Africa. Iliwekwa mnamo 2011-02-07. You must specify title = and url = when using {{cite web}}. (Arabic). Official website of St. Takla Haymanot's Church. Iliwekwa mnamo 2011-02-13. Meyendorff, John (1989). Imperial unity and Christian divisions: The Church 450-680 A.D., The Church in history 2. Crestwood, NY: St. Vladimir's Seminary Press.  "Peter Mongus". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. http://www.newadvent.org/cathen/11770a.htm. "Peter Mongo" in: The Oxford Dictionary of the Christian Church., F. L. Cross and E. A. Livingstone (ed.), London: Oxford University Press, 1974, p. 1074.