There have been many historical instances of markets, exchange, private property, and profit-seeking prior to the 17th century, but whether these social forms constitute capitalism or not depends on your definition of capitalism. I think the most basic definition of capitalism would be an economic system in which the factors of production (i.e. capital) are, by and large, privately owned. Accordingly, any income from the exploitation of these privately owned factors (i.e. profits) is privately appropriated by the owner. I believe this would be a definition that would satisfy economists and historians both in a Marxist tradition (this is, of course, the definition Marx uses) and in classical/liberal traditions (this is also how Joseph Schumpeter would define capitalism, and he was advisor to Paul Samuelson, one of the most influential American economists of the 20th century). Different schools of economic history will add other details: like the role of innovation (for Austrian economists, private property and the profit motive spur innovation) or the market for labor (for Marxist economists, a key component of capitalism is that the large bulk of the population own nothing but their own labor power, which they must exchange on the labor market for a wage) or the process of commodification of land, labor, and money (see Polanyi’s Great Transformation). But as far as identifying where capitalism appears in history, the most fundamental feature is private ownership of the stuff used to make stuff (especially land).
The historical and anthropological evidence, while complex, basically confirms the “conventional wisdom” that most societies prior to the modern era did not have economic systems in which the factors of production (namely land, but also labor) were privately owned (see for e.g. Ellen Meskins Wood 2002). Again, this is not to imply that there was no private property, no market exchange, and no profit-seeking economic behavior. Indeed, markets have existed for as long as there has been human settlement, if not earlier. However, production for exchange on the market (i.e. commodity production), was much more limited. The vast majority of the human population, from the beginning of settled agriculture straight through to the modern era, produced only what they or their collective group needed to subsist (food, mostly, but also shelter, clothing, and tools).
Produce in excess of subsistence needs was paid as tribute/rent/tithe to political or religious authorities and/or exchanged at a market (usually for goods you couldn’t produce yourself). But, for the overwhelming majority of people, it was simply not feasible to produce for market exchange, that is, to become a commodity producer. If you were a subsistence farmer, growing a variety of crops to feed your family, you could not simply decide “Well, if I focused exclusively on growing cabbages, I could realize economies of scale, cut production costs, and sell my cabbages on the market for a profit,” because there was no consumer market for cabbage. People might buy a cabbage here or there, but you couldn’t turn cabbages into a cash crop. So, in summary, there have always been markets, but in pre-modern times markets were not the center of economic activity, as they are now. They existed as a supplement to the main bulk of economic activity.
If you fast forward to the late Medieval and early modern era, you do see the beginnings of commodification (producing goods explicitly for market exchange). Because this requires a high level of organization, investment, and risk, it was usually done with the backing of a political authority (enter mercantilism). Now, there were definitely cases where the commercial enterprise was privately financed for private profit: e.g. Renaissance Venice (and other Italian city-states, esp. Florence), the Hanseatic League, and even earlier merchants in the Arab Golden Age. This period, roughly the 11th-16th century, could be considered the “pre-history” of capitalism, or even a period of “commercial capitalism” (that is, where capitalism, as we have defined it, existed among a small but burgeoning merchant class).
Nevertheless, these ‘private’ activities were rarely entirely private. The early modern history of Italian merchant republics or the Northern European city-states shows that ‘public’ authorities (the church and state) were quite often involved in providing credit to commercial enterprises, sanctioning them through charters, or opening up new markets through military intervention. Moreover, this activity still represented only a tiny share of the overall economic activity of societies, which was still mostly devoted to subsistence agriculture everywhere in the world until the 19th century. And, for major state powers, like kingdoms and empires, private commerce was a minor concern.
