In middle age of England, people invented trusts to avoid the feudal charges and restriction imposed on the land by the lord. The Common Law treated it as normal land deal and didn’t accept and protect the rights of beneficiary. It was the Equity Law who gave the beneficiary the power of enforcement. But why the Chancellor who acted on the behalf of the King did so? People say that the Chancellor did that for justice and conscience, but such argument is weak and inconvincible. From my points of view, there are three reasons. Firstly, the Christianity was the beneficiaries of many trusts and could get enormous economic interests if the law protected the rights of beneficiary. Secondly, the Chancellor could enjoy the interests from trusts directly and to protect beneficiary’s right was to protect his own right. Lastly, the Chancellor was the representative of God and should stop and punish the behavior against the doxies of Christianity. So it is more rational to say that Christianity saves Trusts and Trusts saves Equity Law rather than Equity Law saves Trusts and Trusts saves Equity Law in turn. Otherwise, constitutionalism is another important factor that contributed to the rise of Trusts. The Magna Charta (1215) established a constitutional principle that the King must obey the law, so the King couldn’t stop the Chancellor to accept trusts. Then the system of Trusts established finally.