I would say that the best tools for establishing and preserving freedom are the Constitution, courts, and legislature in general.
The Constitution is a set of laws that all people within one country should follow and it is a document which guarantees their freedom and equality. Courts and other laws do the same thing as well.
The fall of the Mauryan Empire is closely related to the death of Emperor Ashoka. After he passed away, the empire had trouble controlling their financial and economic issues. They also did not have the correct military to protect their empire, so this is how the empire fell.
At first it was kinda of a rocky relationship, but then his daughter Pocahontas begin sending messages to the English, at one point the English may have held her prisoner and her and John Rolfe fell in love and got married this cause a peace treaty until Powhatan dies and his brother became chief