The Vatican has thus far ignored rebel French Archbishop Marcel Lefebvre's latest slap at papal authority.

On Easter Monday, and for the first time in Italy, the traditionalist prelate celebrated the outlawed Latin mass. The Latin, or Tridentine mass -- so called because of liturgy was established at the Council of Trent in the 16th century -- was ordered abandoned by Pope Paul VI in 1969 when he authorized a new liturgy for celebration in the vernacular.

Lefebre, 74, a former superior general of the Holy Ghost Fathers who has vigorously opposed reforms introduced by Vatican II, presided over the service at San Simeone Piccolo, a church in Venice that is no longer consecrated.

Vatican circles had no comment on Lefebvre's action, but Cardinal Mearco, the Roman Catholic patriarch of Venice had warned that Lefebvre's unauthorized mass "can only create suffering in the Venetian Catholic community."

Lefebvre has been under a Vatican-imposed suspension from the exercise of his priestly and episcopal ministry since 1976. Nevertheless, he has continued to defy the Vatican by publicly celebrating the banned mass, administering the sacrament of confirmation, preaching, and ordaining priests.

About 700 Lefebvre supporters from all over Italy, including members of the Italian aristocracy, attended the service in the 18th century Venetian church.

Lefebvre used the occasion to accuse the Vatican cardinals of being "more intransigent that the Soviets," but he carefully avoided any direct reference to Pope John Paul II.

The Lefebvre case seemed to be nearing a satisfactory solution in January 1979, after the rebel archbishop emerged smiling from a series of meetings with the pope and members of the Congregation for the Doctrine of the Faith, the Vatican's watchdog agency over religion and morals.

Since then, although he has continued to ordain priests illegally, he seemed to be avoiding the flamboyant, anti-Vatican gestures which characterized his relationship with the late Pope Paul VI.

But as he celebrated the Tridentine mass on Easter Monday -- with eight other traditionalist priests and 120 seminarians from his seminary at Econe, Switzerland -- he warned the congregation that the church hierachy's continued support of Vatican II and was "a catastrophe."