Strictly speaking these are items of postal stationery, intended for transmission through the post without any form of envelope. The plain, unadorned variety was first used in Austria in 1869 and spread to other parts of Europe (including Britain) a year later. The earliest cards were official postal issues bearing an impressed stamp and having the back and front respectively confined to the message and the address.
From the outset, however, postcards appeared with privately printed matter on them. In Britain this was confined to tradesmen`s advertisements which often included a pictorial motif, but in Europe the pictorial element began as a patriotic sentiment during the Franco-German War (1870-71) and rapidly developed into a popular medium of tourism. In the 1880s and 1890s these souvenir cards took the form of a group of tiny vignettes in the upper and left-hand sides of the `message` side, with the caption `Gruss Aus (German) or `Souvenir de` (French followed by the name of the town or locality.
Picture cards of this type were not permitted in Britain until 1894 when the postal regulations were relaxed sufficiently to allow a small pictorial panel on the message side. Gradually this became larger and all but filled the message side, leaving only a broad margin at the foot of the picture for this purpose. After 1897 messages could also be written on the address side, but only on domestic cards as other countries forbade this. Between 1902 and 1905 other European countries relaxed this rule, and `divided backs` then became more widespread.
The heyday of the picture postcard was the period up to 1915. Many of the cards published in Britain were of German manufacture and the supply was exhausted soon after the outbreak of World War I. Wartime restrictions on paper and printing, followed by a doubling of the postcard rate (1918) and trebling a year later, seriously affected the popularity of the picture postcard, which has never recovered, although it continued to be a relatively popular expression of tourism till 1940. Thereafter successive increases in postal rates diminished their popularity in current use, though with this developed their popularity as collectables, the hobby being known as deltiology.