Postally, the states developed separately - in part because of the differences in currency which made the interchange of mail between them complicated. The use of postal handstamps developed during the 18th century and the spheres of influence were clearly defined by the outbreak of the French Revolutionary Wars.
Between 1851 and 1870 ten states including Lombardy Venetia issued stamps, all imperforate and long the favourite of collectors of classic stamps. Some of the world’s greatest stamp collectors have formed large collections of these atmospheric, philatelic treasures.
From the Bourbon Dynasty Arms of Naples to the Sicilian “Bombas” (so-named as King Ferdinand who also insisted on a postmark which framed his portrait had aggressively supressed insurrection) every stamp has a story to tell. We highly recommend the stamp listings in the Stanley Gibbons Part 8 “Italy & Switzerland” also the various excellent specialised catalogues published by Sassone.