See dragonwriter's point above mine. Specific property rights are not necessary for capital to exist. Can you explain then why the nature of property rights was so different that ownership of it could not be consideres capital? Keep in mind that nobles could in fact sell their land at many points and places during medievil history.

Aditionaly, I made the case that one could say there is no capitalism. Could you explain, then, what capitalism is and why it would somehow only exist from the 18th century or later?