"Dolgopolsky, believes the terms for material culture commonly used to date Proto- Indo-European, such as copper, horse, and wheeled vehicles, cannot be reconstructed in the Anatolian languages and therefore belong to a later, post-Hittite Indo-European and not Proto-Indo-European. Proto-Indo-European, accordingly, did not know all these items, since it was much earlier. He reiterates the arguments outlined previously, suggesting that the horse known to the Proto-Indo-European's was not the domesticated but the wild variety, and claims that the word *ayes did not originally refer to copper but to metal in general, and it may then later have been transferred to copper in some countries when this metal entered common usage: "Hence none of these words can serve as evidence for dating Proto-IE"."