In Cook v. Horn (214 Ga. 289, 104 S.E.2d 461 (1958)), Cook made a revocable inter vivos trust that provided a life income to his children, and then at the death of the last child, the remainder was to be given to his grandchildren. Therefore, the time the interest vested was at the death of his last child. There was a question as to whether the trust violated the Rule Against Perpetuities. If Cook had a child after the trust was created, and that child survived more than 21 years after the death of all the other children. That would violate the Rule Against Perpetuities, because the interest would not vest until more than 21 years after the death of all lives in being at the creation of the trust. However, Cook's trust was revocable. Therefore he had the ability to change it up until his death. Theoretically, he could have changed the trust if he had another child. Therefore, the time the trust was created is defined as the time the trust became irrevocable, which was Cook's death. Since Cook couldn't have any children after he died, all of his children would have to be lives in being at the time of the creation of the interest. Therefore the trust doesn't violate the Rule Against Perpetuities. Had this been an irrevocable trust, then the creation of the interest would have been the time the trust was created and it would be void because it could possibly violate the Rule Against Perpetuities.