There is much discussion about the essential requirements for the consecration of a bishop. Traditionally, there has been the Roman Catholic doctrine of matter, form, and intent. This essentially says that one must intend to do what the Church does using the laying on of hands and the consecratory preface. While these scholastic terms are the legal requirements for Roman Catholics, they also are the general requirements for all other churches within the apostolic succession.
There is frequent discussion about the solo consecration of a bishop by another bishop. Generally, the desirable thing is to have two or three bishops together consecrating a new bishop. This ensures that (1) the consecration is valid if the principal consecrator lacks valid orders and (2) the collegiality of the neighboring churches gathered around the Eucharist. Indeed, there are ancient texts that speak to the necessity of having multiple bishops participate in consecrations:
Canon 13 of the Council of Carthage: That a bishop should not be ordained except by many bishops, but if there should be necessity he may be ordained by three.
Canon 1 of the Apostolic Canons: Let a bishop be ordained by two or three bishops.
Yet, this practice is not always followed. There are points when it could not be followed because of persecution, inability to secure another bishop, etc. Below are some interesting historical precedents that point to places in history that prove that one is still valid when consecrated solo. Included are Old Catholic, Roman Catholic, and Orthodox examples of solo consecrations which were (often) conducted even in secret.
- Bishop Dominique Marie Varlet, beginning in 1724, consecrated Steenoven, Barchman, van der Croon, and Meindartz.
- Bishop Josaph (Bolotav), the first Russian Orthodox Bishop of Alaska, was consecrated in 1799 by Bishop Benjamin of Irkutsk upon orders from the Holy Synod to perform that consecration alone.
- Bishop Michel d'Herbigny (pictured), beginning in 1926, consecrated Pie Neveu, Aleksander Frison, Boleslavs Sloskans, and Antonio Malecki solo.
- Bishop Matthew (Karpathakis) of Bresthena consecrated the bishops of the Greek Old-Calendarist Church solo in 1940.
- Bishop Barnabas of Cannes of ROCOR consecrated Lazarus of Tambov solo in 1982.
There are also numerous examples of solo consecrations by Bishops Thuc, Alfredo Gonzalez, etc. This list is just to provide a few examples of solo consecrations.