By Tobias Carroll If you were thinking about buying an artifact that dated back to the time of ancient Rome, how would you go about purchasing it? Every once in a while, a major auction house will hold some sort of event at which rare artifacts are up for sale. But as it turns out, every once in a while your local Goodwill might end up with a really great deal on an ancient artifact. No, this isn’t the subject of a comedic sketch with a “That belongs in a museum” punchline. It’s what one Laura Young discovered in a Goodwill in Austin one day in 2018. Young, a dealer in antiques, noticed someth…