Reprint of the seminal work (1638) by the Milanese Jesuit in Rome Pietrasanta, who first invented the method, still in use, for describing the metals and colours of a coat of arms by differently oriented traits; several thousand coats of arms enrich the text, a real heraldic monument. It is also a very useful ordinary of the European nobility, as it allows to find, from the heraldic elements of a coat of arms, the family using it; also, for the coats of arms displayed, the author also mentions their sources, with a remarkable historic method, quiete uncommon in the Seventeenth Century.