For centuries, the fiduciary duties owed by a trustee to his or her beneficiaries formed the core, indeed definitional, component of a trust, something arising from the relationship itself. Thus, the Restatement (Second) of Trusts could confidently proclaim:
A trust … is a fiduciary relationship with respect to property, subjecting the person by whom the title is held to equitable duties to deal with the property for the benefit of another person…
This fiduciary relationship, of course, is not the exclusive province of trust law. It also governs the relation of guardian and ward, agent and principal, attorney and client, corporate director and shareholder, as well as the relations among partners.