I can't go quite as far back as the 12th-15th centuries, but similar theories about economics in later periods do commonly mention those types of people as the original entrepreneurs. Richard Cantillon is probably one of the earliest to discuss the different classes of laborers in his 18th century in his Essai sur la Nature du Commerce en Général (Essay on the Nature of Trade in General). In this essay, he defined the land as the key source of value and all people in the economy fell under three main categories: the land owners, the laborers and the entrepreneurs - the people who took the goods that were produced in areas and transported them to the market. In fact, Cantillon was the inventor of the phrase that we now use today. He then wrote about other key ideas such as the circular flow of the economy, but those are not quite as relevant to the question. The larger point is that there would always be a class of people in the economy who facilitated trade by taking goods from one area to another so as to properly circulate the capital in the market. His theories and characterizations of classes became adapted by the dominant economic model of the 18th century French Physiocrats who reclassified his categories as landowners, tenant farmers and artisans but kept the ideas of a circular flow of money.

So as I can best give an answer, yes there were some amount of people who would travel from village to village selling their goods as this was incorporated into the early economic theory of Europe. And to the same extent, it somewhat matches the ideal of the American dream as people would take control of their own wages. I can't speak so much as to how similar this was to other early economies as that is outside of my area of study, but I hope this was at least somewhat helpful.