Apprenticeship indenture of Joshua W Mulholland.

The indentured apprenticeship is an older system of on-the-job training going back to the Middle Ages. Apprentices signed a contract known as an "indenture," binding them to serve a company for five years in exchange for learning his trade.

Modern apprentices still sign a contract that is still sometimes called an indenture, but the terms of the indentured apprenticeship are much less demanding today than the historical apprenticeship indenture.