The Pope is hoping that by entering the Umayyed mosque in Damascus - the site of the tomb of John the Baptist - he will underline his attempts to bring Christianity and Islam closer together.
Officials organising the Pope's itinerary, said it would be the first time that Christians and Muslims would pray together in an organised way.
The Pope, 80, would lead the Christian side of the prayer and Syria's mufti, Sheikh Ahmed Kataro, the Muslim side.
Footsteps of Paul
In 1986, Pope John Paul was the first Pontiff to enter a synagogue after he visited one in Rome.
The mosque visit is scheduled for 6 May in the middle of the pope's three-day pilgrimage to the Holy Lands, which has already taken him to Egypt, Jordan, Israel and the Palestinian territories.
The mosque, known as the Great Mosque of Damascus and one of Islam's most celebrated shrines was once the site of an Aramaic temple.
Then, in the first century AD, a Roman temple dedicated to Jupiter was built on the site, before being converted into a church dedicated to Saint John the Baptist.
Saint John is also venerated by Muslims as the prophet Yahya.
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