"Ancient" is most commonly used to describe something that dates from a long time past in historical or archaeological terms. This would be the most accurate way to describe an artifact from the 12th century. "Aged" is most often used in the case of things that are purposefully brought to their point of maturity, such as wine and cheese. "Geriatric" is a word that refers to the elderly, while "old" describes any item that has existed for a long time, or that cannot be called "new" any longer.
