VATICAN CITY — On Tuesday Pope Francis approved a way for the Church to recognize marriages celebrated by priests of the Society of St. Pius X, which before now were not considered valid by Church authorities.

Through a letter published April 4, the Pope has given diocesan bishops, or other local ordinaries, the authorization to grant priests of the SSPX the ability to licitly and validly celebrate the marriages of faithful belonging to the society.

The authorization is granted under the condition that a diocesan, or otherwise fully regular priest, is delegated to hear and receive the consent of the parties during the marriage rite itself, which can then be followed by the celebration of the liturgy by a priest of the society.

Francis approved this authorization following a proposal by the Congregation for the Doctrine of the Faith and the Pontifical Commission Ecclesia Dei, as a way to ensure the validity and lawfulness of the sacrament and to “reassure the conscience of the faithful,” the commission’s letter explains.

“Despite the objective persistence of the canonical irregularity in which for the time being the Society of St. Pius X finds itself, the Holy Father … has decided to authorize local ordinaries the possibility to grant faculties for the celebration of marriages of faithful who follow the pastoral activity of the society,” the letter states.

If the first provision is not possible, or if no priests of the diocese are able to receive the consent of those marrying, then the local ordinary, most commonly the bishop of the area, may then grant the priest of the society presiding over the Mass the necessary faculties to receive the consent in the marriage rite.

In this case, the priest of the society is obliged to then send the relevant documents to the diocesan Curia as soon as possible.

Signed by Cardinal Gerhard Müller, prefect of the congregation, and Archbishop Guido Pozzo, secretary of the commission, it explained the effort as part of the Church’s ongoing initiatives “to bring the Society of St. Pius X into full communion.”

The most recent of these initiatives was the September 2015 announcement by Pope Francis that the faithful would be able to validly and licitly receive absolution from priests of the SSPX during the Jubilee Year of Mercy. This ability was later extended indefinitely by Francis in his apostolic letter Misericordia et Misera, published Nov. 20, 2016.

The SSPX was founded by Archbishop Marcel Lefebvre in 1970 to form priests, as a response to what he described as errors that had crept into the Church after the Second Vatican Council. Its relations with the Holy See became particularly strained in 1988, when Archbishop Lefebvre and Bishop Antonio de Castro Mayer consecrated four bishops without the permission of Pope John Paul II.

The illicit consecrations resulted in the excommunication of the bishops involved. The excommunications of the surviving bishops were lifted in 2009 by Benedict XVI, and, since then, negotiations “to rediscover full communion with the Church” have continued between the society and the Vatican.

In remitting the excommunications, Benedict noted that “doctrinal questions obviously remain, and until they are clarified, the society has no canonical status in the Church and its ministers cannot legitimately exercise any ministry.”

The biggest obstacles for the society’s reconciliation have been the statements on religious liberty in Vatican II’s declarations Dignitatis Humanae and Nostra Aetate, which the SSPX claims contradict previous Catholic teaching.