Barlaam and Josaphat are said to have lived in third or fourth century India, where the Gospel was first preached by St Thomas the Apostle. The religion had grown steadily, but was persecuted by, among others, one King Abenner. This king was told by his astrologers that his son Josaphat would become a Christian. King Abenner kept his son locked away from the outside world to prevent this prophecy from coming true, but a Christian hermit named Barlaam preached the Chrsitian religion to the young prince, and he converted. King Abenner later became a Christian and then a hermit. Josaphat became king, but abdicated soon after to live a life of ascetic piety.
Josaphat's tale was wildly popular in the Middle Ages, and versions of it appeared in nearly all European languages, from Armenian to Icelandic. It was the basis of La vida es sueño (Life is a dream), the masterpiece by Spanish Golden Age playwright Pedro Calderón de la Barca. The legend quite nearly circumnavigated the globe; a version of it came into being in the Tagalog language of the Philippines.
The story, it turns out, is a Christianized retelling of the story of Prince Siddhartha Gautama, the Buddha. Before his birth a seer predicted he would either be a great king or a holy man. To ensure the former outcome, his father the king shielded the boy from all forms of religious teaching and from witnessing any form of human suffering. Having accidentally witnessed the latter, he left his palace to lead an ascetic life. The Buddha's story traveled in all four directions. As it traveled west, the Sanskrit "Bodhisattva" became "Bodisav" in Persian, "Budhasaf" or "Yudasaf" in Arabic, "Iodasaph" in Georgian, "Ioasaph" in Greek, and "Josaphat" in Latin.
Thus, the Buddha came to be venerated in Christendom. This remarkable origin of this tale need not be cause for embarrassment. It is a testimony to the faith of the Age of Faith, whose children yearned for holiness and recognized it when they saw it, even in a tale from a faraway land. Without access to a fact-checking resource like Wikipedia, it is easy to see how such a cultus could have developed.
Were the Christians of the Middle Ages who asked for St Josaphat's intercessions praying to the Bodhisattva? Were the many parishes named after St Josaphat erected in honor of the Buddha?
MORE at the Western Confucian's interpretation of what this could mean to the Church.