The lack of a coherent institution narrative in the Anaphora of Addai and Mari, which dates to apostolic times, has caused many Western Christians, and especially Roman Catholics, to doubt the validity of this anaphora, used extensively by the Assyrian Church of the East, as a prayer of consecration of the eucharistic elements. In 2001, after a study of this issue, Cardinal Joseph Ratzinger (later Pope Benedict XVI), then Prefect of the Congregation for the Doctrine of the Faith, promulgated a declaration approved by Pope John Paul II stating that this is a valid anaphora. This declaration opened the door to a joint synodal decree officially implementing the present "Guidelines for Admission to the Eucharist between the Chaldean Church and the Assyrian Church of the East", which the synods of the Assyrian Church of the East and the Chaldean Catholic Church signed and promulgated on 20 July 2001.