I have seen quoted in the name of Marsilio Ficino (1433-1499), also spelled Marcellus Ficin, that all nations of the world worship a God whose name is spelled with four letters. Does anybody know where this might occur in Ficino's writings and if there has been any discussion of Ficino's assertion? The source where I saw this quoted was in The Concilliator by Rabbi Manasseh ben Israel of Amsterdam (1604-1657), see here on Google Books.