Professor Mueller attributes the first recognition of the identity of the two stories to M. Laboulaye in 1859.  But in fact I find that the historian de Couto had made the discovery long before.[5] He says, speaking of Budao (Buddha), and after relating his history: 

“To this name the Gentiles throughout all India have dedicated great and superb pagodas.  With reference to this story we have been diligent in enquiring if the ancient Gentiles of those parts had in their writings any knowledge of St. Josaphat who was converted by Barlam, who in his Legend is represented as the son of a great King of India, and who had just the same up-bringing, with all the same particulars, that we have recounted of the life of the Budao....  And as a thing seems much to the purpose, which was told us by a very old man of the Salsette territory in Bacaim, about Josaphat, I think it well to cite it:  As I was travelling in the Isle of Salsette, and went to see that rare and admirable Pagoda (which we call the Canara Pagoda[6]) made in a mountain, with many halls cut out of one solid rock ... and enquiring from this old man about the work, and what he thought as to who had made it, he told us that without doubt the work was made by order of the father of St. Josaphat to bring him up therein in seclusion, as the story tells.  And as it informs us that he was the son of a great King in India, it may well be, as we have just said, that he was the Budao, of whom they relate such marvels.” (Dec.  V. liv. vi. cap. 2.)

Dominie Valentyn, not being well read in the Golden Legend, remarks on the subject of Buddha:  “There be some who hold this Budhum for a fugitive Syrian Jew, or for an Israelite, others who hold him for a Disciple of the Apostle Thomas; but how in that case he could have been born 622 years before Christ I leave them to explain.  Diego de Couto stands by the belief that he was certainly Joshua, which is still more absurd!” (V. deel, p. 374.)

[Since the days of Couto, who considered the Buddhist legend but an imitation of the Christian legend, the identity of the stories was recognised (as mentioned supra) by M. Edouard Laboulaye, in the Journal des Debats of the 26th of July, 1859.  About the same time, Professor F. Liebrecht of Liege, in Ebert’s Jahrbuch fuer Romanische und Englische Literatur, II. p. 314 seqq., comparing the Book of Barlaam and Joasaph with the work of Barthelemy St. Hilaire on Buddha, arrived at the same conclusion.

In 1880, Professor T.W.  Rhys Davids has devoted some pages (xxxvi.-xli.) in his Buddhist Birth Stories; or, Jataka Tales, to The Barlaam and Josaphat Literature, and we note from them that:  “Pope Sixtus the Fifth (1585-1590) authorised a particular Martyrologium, drawn up by Cardinal Baronius, to be used throughout the Western Church.”.  In that work are included not only the saints first canonised at Rome, but all those who, having been