An official meeting between Pope Francis and Imam Ahmed al Tayyeb will take place Monday at the Vatican, signaling a new step in Catholic-Muslim relations.

“An audience between the Pope and the Great Imam of al Azhar is being prepared for Monday,” Vatican spokesman Fr. Federico Lombardi told journalists May 19.

He said the schedule for the visit “still has to be defined,” but confirmed that the meeting will take place Monday, May 23.

The Imam of al Azhar, currently Ahmed al Tayyeb, is considered by some Muslims to be the highest authority in Sunni Islam and oversees Egypt’s al-Azhar Mosque and the prestigious al-Azhar University attached to it.

Founded in the Fatimid dynasty in the late 10th century together with the adjoining mosque, the university is one of the most renowned study centers for the legal principals of Sunni Islam.

According to Fr. Lombardi, the Egyptian university is also considered to be “the most authoritative theological-academic institution of Sunni Islam.”

In 1961 Egyptian President Gamal Abdel Nasser “secularized” the university by including a curriculum which isn’t exclusively religious. However, the underlying principles have remained the same.

The meeting between Pope Francis and the Great Imam of al Azhar has been in the works since February, when Bishop Miguel Àngel Ayuso Guixot, secretary of the Pontifical Council for Interreligious Dialogue, and the apostolic nuncio in Egypt, Archbishop Bruno Musarò, visited the al-Azhar Mosque and University.

During their visit, Bishop Ayuso gave Cardinal Jean-Louis Tauran, President of the Pontifical Council for Interreligious Dialogue, a letter expressing his willingness to meet with the Grand Imam and to accompany him for an official audience with the Pope.

The meeting between the two is seen as a thawing of relations between the al-Azhar institution and the Holy See, which were strained in 2011 with claims that Pope Benedict XVI had “interfered” in Egypt’s internal affairs by condemning a bomb attack on a church in Alexandria during the time of Coptic Christmas.

Relations under Francis have improved with his constant appeals for interfaith dialogue. Shortly after his 2013 election, Pope Francis sent a personal message to Muslims marking the end of the first month of Ramadan.