"a bishop ought to be chosen by all the bishops of his province, but if that is impossible because of some urgent necessity, or because of the length of the journey, let three bishops at least assemble and proceed to the consecration, having the written permission of the absent." Consecrations by the Pope were exempt from the three bishop requirement.

The reason for the three bishop requirement was stated by St. Isidore: "[The custom] that a bishop should not be ordained by one bishop, but by