In the autumn of 1549, a holy man and his companion began wandering the Satsuma domain of southern Kyushu, preaching the glory of the Sun Buddha Dainichi. The man, who called himself a so (monk), was reported to come from the "Land of Buddha" and exhorted any who would listen to follow Buppo (the Law of the Buddha). If they did, he may have promised, they would attain naisho (enlightenment) and experience raigo (a welcome to the Pure Land by Amidha Buddha and attendant bodhisattvas).
That man was no Buddhist priest, but Francis Xavier (1506-52), the first Catholic missionary -- and one of the first Europeans to set foot in Japan. The Jesuit had traveled from Rome, via India (the Land of Buddha), to spread the gospel.
What followed, however, were two years of linguistic and theological chaos as, on the advice of his interpreter -- an ill-educated Japanese who converted to Christianity after stowing away on a Portuguese ship -- Xavier preached the Word using "equivalent" Buddhist terms.