This type of infallibility falls under the authority of the sacred magisterium. The doctrine of papal infallibility was formally defined at the First Vatican Council in 1870, although belief in this doctrine long predated this council and was premised on the promises of Jesus to Peter, promises to Peter (Mat 16:16-20; Luke 22:32). The encyclicals of the First Vatican Council, however were rejected by a small minority of bishops who separated themselves from union with the Bishop or Rome to form, or preserve, the Old Catholic Church. The ordinary and universal episcopal magisterium is considered infallible as it relates to a teaching concerning a matter of faith and morals that all the bishops of the Church (including the Pope) universally hold as definitive and only as such therefore needing to be accepted by all the faithful. This aspect of infallibility only applies to teachings about faith and morals as opposed to customs and prudential practices. Additionally, the ordinary and universal episcopal magisterium applies to a teaching to be held definitively by all the bishops at any given moment in history. Such teachings are extremely hard to prove. Thus, even if a teaching on a matter of faith and morals is out of favor among the bishops of a later date, once it has been held definitively by all bishops to be accepted by the faithful as infallible, then it is considered infallible and unchangeably true. However, Bishops all agreeing to a teaching to be held inconclusively are not teaching it to be definitive. It must be clearly established to be definitive for all time. This was attempted to be thoroughly done and documented in the case of several statements contained in Evangelium vitae. The Eastern Orthodox Churches also believe in apostolic succession through which Christ promised to preserve the Church from teaching error. This grace and authority, however, does not make any of the bishops being individually infallible, however, but rather means that, in consensus, in combined agreement, they are charged with preserving the universal faith from error. Thus the Orthodox Church does not use the term "infallible" to discuss the works of any bishop or council. Orthodox Christians regard the concept of infallibility to be uniquely Western and therefore avoid the use of defining or terming even Ecumenical Councils as infallible. Ecumenical Councils are felt, in the East, to be a continuation of the apostolic faith, and that the apostolic faith does not change. However, it also believes that not every council that proclaims itself ecumenical is so in fact.