Plucknett writes "It was the mediaevalists in England, armed with Bracton and the Year Books who ended Stuart statecraft. The Constitution of the United States was written by men who had Magna Carta and Bracton, and Coke and Littleton before their eyes. Could anything be more medieval than the idea of due process or the insertion in an instrument of government a contract clause? 'Pacta sunt servanda' (Pacts should be kept) became a motto of Edward I. The result can be traced directly to the work and writings of Bracton.