As the growing middle class in the late Middle Ages found themselves at leisure to travel for pleasure, a tourism industry arose in Europe for the first time. The travelers were pilgrims, choosing as their destinations holy sites across Europe (though the motivation for making a trip at all was not always purely a religious one). And, of course, people in the places to which they traveled excelled at profiting from the new arrivals.
Just as for travelers today, a short voyage was always easier than a long one, and so many of thepopular pilgrimage sites were small local shrines dedicated to a minor saint in the area or to a miracle that had purportedly occurred there. But many of the larger ones, often associated with a more important saint and their relics, were able to draw in pilgrims from across Europe, a fact which the religious community associated with the destination often actively encouraged. In fact, there are known surviving pamphlets in which the miraculous nature of one Marian shrine is praised as being more efficacious than other, competing shrines to the same Virgin. Booklets were printed which recounted miracles associated with the local saint; these could be brought home by the pilgrims as a keepsake, but they would then also serve to promote the destination to the traveler's friends, who might then make their own trips. Inns were often established along popular pilgrimage routes; in fact, church-supported lodging along the path from Roncesvalles (where French pilgrims crossed the Pyrenees) to Santiago de Compostela in northwestern Spain is a tradition which persists to the present day, and many people each year continue to make the month-long trek on foot along the traditional route.
One of the most popular pieces of memorabilia for pilgrims was not the books, nor the dubious relics sold at or near certain shrines (it was commonplace for pilgrims to purchase slivers of the True Cross while in Jerusalem, for instance), but stamped or molded pewter badges. Small and cheaply made, these are roughly flat images shaped on one side in low relief, often sold as keepsakes. They're often shaped like something significant to the shrine, whether it's the relevant saint themself or an emblem. (Pilgrims to Rome, for instance, often returned home with a badge in the shape of a key, representing St. Peter, who holds the keys to the Kingdom of Heaven.) Sometimes the association wasn't particularly derived from anything more than tradition; the scallop shell, for instance, came to represent St. James the Great (Santiago), and so badges in that shape were made and sold at his shrine at Compostela.
At some times and places, a special patent was granted to the religious institution that ran the shrine on the minting of pilgrim badges, so other vendors came up with their own non-infringing designs. As a result, we see many pewter badges which serve entirely as cheap jewelry without a religious significance at all; much like the things seen in the souvenir shops that line the main drag of any tourist town today, these range in style from cloyingly sentimental to humorous (often in a very lowbrow way), and many have no connection to the place they were made. Popular designs included heart motifs to represent love, as well as various popular heraldic charges. In many cases the more comedic designs revolve around genital imagery. Winged or feathered penises were popular, apparently especially in the Low Countries; other badges depicted disembodied vulvas with arms and legs.
Folklore held that throwing a pilgrimage badge into running water brought good fortune, and so it is common for them to be found in and along rivers today. They turn up in numbers that attest to the vibrancy of the cheap tourist trinket industry from the fourteenth century into the early modern period.