Numismatist noted numismatist who was not an avid collector, and King Farouk I of Egypt was an avid collector who had very little interest in numismatics. Harry Bass by comparison was a noted collector who was also a numismatist. The second group are the coin dealers. Often called professional numismatists, they authenticate or grade coins for commercial purposes. The buying and selling of coin collections by numismatists who are professional dealers advances the study of money, and expert numismatists are consulted by historians, museum curators, and archaeologists. See, for example, the International Association of Professional Numismatists (IAPN) and the British Numismatic
Henry Cohen (numismatist) 1854, dealt with the Roman Republican coinage, while the second, issued in 8 volumes from 1859 to 1868, focused on the coinage of the Roman Empire, from Pompey to Romulus Augustus (49 BC - 476). Besides his numismatic works, Cohen wrote several compositions, one of which, the opera "l'Impératrice", was performed, about 1834, in Naples, Paris, and London. Moreover, he published four tracts about musical theory. Henry Cohen (numismatist) Henry Cohen (Amsterdam, 21 April 1806 – Paris, 17 May 1880), was a French numismatist, bibliographer and composer. Cohen moved from Amsterdam to Paris, where he worked as a music teacher