The International Association of Amateur Heralds

Archbishop Bruno Heim was the nearest thing the Papacy got to an Heraldic Authority in modern times (though starngely he was opposed to the creation of such an institution). His own CoA drove a coach and horses through the tincture convention, which is perhaps why he wrote a book defending metal/metal and colour/colour as valid.



http://en.wikipedia.org/wiki/Bruno_Heim

actually these were his family arms with the addition of the star. He wrote the book because he found it odd that his family has such arms and wanted to find out about the rule and his research indicated that it was not as ancient a rule as indicated in the (later) heraldry manuals.