The duty of loyalty is often called the cardinal principal of fiduciary relationships, but is particularly strict in the law of trusts. In that context, the term refers to a trustee's duty to administer the trust solely in the interest of the beneficiaries, and following the terms of the trust. It generally prohibits a trustee from engaging in transactions that might involve self-dealing or even an appearance of conflict of interest. Furthermore, it requires a fiduciary to deal with transparency regarding material facts known to them in interactions with beneficiaries.