According to the Austrian art historian Alois Riegl (1857–1905), cultural heritage possesses age value (Alterswert) based on the perception of an object’s visible traces of age. His 1903 essay “The Modern Cult of Monuments” became a classic, and age value has ever since been constitutive for cultural heritage. Closer scrutiny, however, reveals that clever copies, reconstructions, and imaginative inventions can possess age value too. I therefore suggest “pastness” as a useful term for denoting the perception that a given object is “of the past.” Pastness is not immanent in an object but, rather, results from its appearance (for example, patina), its context (for example, in a museum), or its correspondence with preconceived expectations among the audience. In this article, I review the concept of pastness and discuss its implications for the global heritage sector. Age value emerges as being less universal than Riegl thought and was linked to a very particular intellectual and cultural context.