Wilfred Cantwell Smith traced the story from a second to fourth-century Sanskrit Mahayana Buddhist text, to a Manichee version, to an Arabic Muslim version, to an eleventh century Christian Georgian version, to a Christian Greek version, and from there into Western European languages.

Another theory has recently arisen, propagated by author Holger Kersten. "Josaphat," according to Kersten, is derived from the Arabic "Judasaf." Unfortunately, in Arabic, the letters J and B were often confused, so a more literal translation would be "Budasaf," as it is written in an Urdu version of the tale. This not only is a possible tie to the Sanskrit term "bodhisattva," but also a tie to the Jesus-in-India theory, which claims he later used the name 'Yuz Asaf' and that this story refers to him. The Urdu version seems to support this, as it includes details similar to the recorded life of 'Yuz Asaf' in Kashmir.

He should not be confused with Saint Josaphat Kuncevyc (in fact, if you follow certain theories, he might be Jesus Christ); nor should Saint Barlaam be confused with Saint Barlaam of Calabria.