'It is therefore frequently asserted that the story of Barlaam and Ioasaph originated as a Persian, probably Manichæan, retelling of the the life of Buddha, whom Mani numbered among the prophets. On the other hand, the most famous and central episode in Gautama's life, his enlightenment under the Bodhi tree, is entirely lacking, and there is an equally complete absence of distinctively Buddhist theology or doctrine. ... Curiously, in spite of the existence of an Ethiopic version, the occurrence of at least one Nubian place name in the Greek, and the marked resemblance of the setting to the Axumite Empire, scholars do not seem to have suggested that the story might have roots in the African as well as the Indian "Æthiopia".' http://ecole.evansville.edu/glossary/barlaam.html
I have noticed that Sir Henry Yule, translator and editor of a nineteenth century edition of the Travels of Marco Polo published circa 1900 takes the same opinion about the Buddhist origin of the story of Saints Joasaph and Barlaam. The Buddhist theory is not new, but it seems to have originated with agnostics in protestant countries - not from Orthodox Christians who take the story at its word.
Funny how those who do not believe the story and argue for a non-Christian origin just so much ignore the black African Christian evidence.
Aside from the disqualifications of the buddhist theory mentioned above is that to argue that the story is in fact based on Buddha and not what it says internally is to make a liar out of the canonical Orthodox calendar of Saints and the holy synods who canonized them.
It is to say that the Orthodox Church does not have clue about the history of the saints whom it canonizes. The Buddhist theory about Saint Joasaph can be found in books by nineteenth century european and american agnostics. IS it not reasonable to suggest that this nineteenth century theory about Buddhism ignores the possibility of an African Christian historical setting because due to crude racism?
The fact that an African Christian historicity of this story would not barbarically violate its internal cohesiveness as the theories of agnostic intellectuals with no faith that dig through ancient Christian manuscripts and then issue their opinions about it as taken from Buddhism.
My theory about the theory: Modern atheists are biased towards the Buddhist religion because it closely identifies with their own faith.
That is the essence of Blavatsky and theosophy, and that is kind of spirit which I discern in such a theory.