'''''Episcopi vagantes''''' (Latin for "wandering bishops") are persons who have been [[ordination|ordained]] as [[bishop]]s in some irregular fashion, especially those claiming to have valid [[Roman Catholic Church|Roman Catholic]] orders although their ordinations were not authorized by the Roman Catholic Church.
The Vatican considers some such ordinations "valid" but "unlawful," but the Orthodox Church considers them simply not to be ordinations and thus also considers persons so ordained not to be bishops at all. This is because unlike the Vatican, it considers [[apostolic succession]] to exist only in bishops who are regularily ordained by bishops that are neither themselves defrocked, nor teach heretical teachings. Holy Orders are not regarded by the Orthodox as "indelible," thus if a bishop breaks from the Church, his episcopacy (and thus his ability to ordain) does not follow him.
Many of these claim succession from the see of Utrecht, or from Orthodox or [[Eastern Rite Catholic]] churches; others from Roman Catholic bishops that have ordained their own bishops after disputes with the Vatican. Such lines continue to persist because of the more mechanistic understanding of apostolic succession which the Roman Catholic Church has—that is, if a "valid" bishop ordains a man using the proper rituals, then he is "valid" as well, even if neither has any living connection to the Church. The Orthodox understanding, however, necessarily presupposes the impossibility of ''episcopi'' that are ''vagantes'', for the ministry of the episcopacy resides only ''within'' the Church.
Many ''episcopi vagantes'' will style their churches variously as ''Orthodox'', ''Catholic'', ''Apostolic'', or any of the other historical names used by the Church. Attempting to trace their roots, delineate one group from another, or easily identify them as being ''episcopi vagantes'' can be a difficult matter, especially because such groups seem to be subject to internal [[schism]]s and name changes. One indication often pointed out about the webpages of such groups is that they often have a list of their alleged apostolic succession displayed prominently up front and/or lengthy insistence on their legal ownership of various registered trademarks (usually the group's name).
*Many people have claimed ordinations as bishops where it is questionable whether the ordination ever actually took place, which is a separate issue.
Further, bishops belonging to groups which are in [[ schism]] (i.e., out of [[full communion]]) from the Church or have suspended [[concelebration]]s are not ''episcopi vagantes'' inasmuch as their consecrations as bishops were clearly within the Church and the break in communion may well only be temporary.
*''The Oxford Dictionary of the Christian Church, 3rd ed.'', pp. 555, 1054, 1698
*[http://www.ind-movement.org/ Ind-Movement.org], "Your Complete Guide to the World of Autocephalous ('Independent-Movement') Churches in the Apostolic Succession"
*[http://www.nestorian.org/unofficial_home_page_of_the_on.html Unofficial Home Page of The One Holy Catholic and Apostolic Church]