The Pauline monastery at Jasna Góra (Lat.: Clarus Mons) in Częstochowa is the foremost centre of religious life in Poland, and one of the best known Marian sanctuaries in Europe and the world. The tradition of pilgrimage to the miraculous painting of Our Lady of Częstochowa dates back to the end of the 14th century; in 1382 Władysław, Duke of Opole invited a group of Pauline fathers (Ordo Sancti Pauli Primi Eremitae) to be the custodians of the little church on the hill dedicated to the Madonna. The object of cult is the Old Ruthenian icon of Our Lady of Częstochowa, also known as the Black Madonna. According to tradition, it was painted by St Luke the Evangelist on a piece of the table at which the Holy Family ate their meals. Many Polish kings, artists and scholars have prayed before the painting, and even today some four million pilgrims come to Częstochowa every year, around 150,000 of them on foot (the annual pilgrimage from Warsaw, for instance, takes nine days, and is made by around 8,000 people). Pilgrimages made on foot, as a type of retreat combining prayer, fellowship and physical effort dedicated to God, are still very popular in Poland.