The Anglo-American trust is an invention of the judiciary, specifically the English Court of Chancery. The will, a testamentary instrument, on the other hand, is a creature of statute. The testamentary trust is a product of the direct intersection of will doctrine and trust doctrine. The inter vivos trust is not. That having been said, when it comes to the administration of an inter vivos trust, the two doctrines will occasionally indirectly intersect. Charles E. Rounds, Jr. explains in §8.26 of Loring and Rounds: A Trustee’s Handbook [pages 1326-1328 of the 2015 edition], which is reproduced in its entirety below.