Anything made or modified by a human can be considered an artifact, though the word is often used to describe old, mundane objects, like stone tools or bits of broken pottery. In the context of art history, even the most fragmentary or banal artifacts often contain facinating information about the time and place they were created. A simple clay pot may be able tell you about the diet, commerce, manufacturing technologies, and aesthetic values of a culture that left no written language. Pretty cool.