Traditionalist Archbishop Marcel Lefebvre heralded the first split in the Roman Catholic Church in more than a century with an announcement Wednesday that he will consecrate four bishops June 30.

The consecration, without papal authority, seems certain to lead to the excommunication of Lefebvre and the first schism since the Old Catholics broke from Rome in 1870 because they refused to accept the dogma of papal infallibity.Speaking at a news conference, the 82-year-old founder of the traditionalist St. Pius X Fraternity announced that these four traditionalist priests will be consecrated June 30:

-The Rev. Bernard Tissier de Mallerais, secretary general of Lefebvre's fraternity.

-The Rev. Richard Williamson. head of the Traditionalist Center in Ridgefield, Conn.

-The Rev. Alfonse de Gallereta, head of the Traditionalist Center in Buenos Aires, Argentina.

-The Rev. Bernard Felley, chief administrator of the fraternity, a Swiss national.

The rupture followed months of efforts pushed by Pope John Paul II to work out a reconciliation with Lefebvre, suspended since 1976 from his priestly functions for revolting against the church reforms.

Lefebvre holds that modernistic trends, condemned by the patron saint of his society, assumed "self-destructive" proportions in the reforms instituted by the Second Vatican Council 1963-65.

He is the only archbishop in the traditionalist movement but claims several other bishops share his traditional views.

In defiance of the 1976 order by Pope Paul VI, barring him from saying Mass and giving the sacraments, he has ordained more than 200 priests. They continue to use a 16th century Latin rite, the forbidden Tridentine Mass.

His movement claims millions of followers throughout the world.

Lefebvre has said he would ignore an act of excommunication. Ejection from the church is the Vatican's most drastic sanction.

In a 1976 interview with The Associated Press, he said: "It is not we who have entered into schism. It is the pope who causes schism to the extent to which he breaks with the church traditions."

Anti-Vatican rhetoric has been less sharp since John Paul II became pope. But Lefebvre's announcement last year that he is considering the consecration of bishops brought new tension.

He spoke of new evidence that the Vatican was plunging into the "darkness of errors." He cited a 1986 meeting Pope John Paul organized with the leaders of many world religions and a "disappointing" response he received from the Vatican to questions concerning religious freedom.

Lefebvre opposes the strengthening of contacts with Protestants and other Christian religions.

"True ecumenism consists of trying to bring home the lost sheep," said the Rev. Franz Schmidberger, who succeeded Lefebvre as superior general of the Fraternity.