The Constitution of the Church in Wales was made to facilitate and order its public life. Drafted on the eve of disestablishment, the Constitution has been changed piecemeal over the past 100 years. While today its fundamentals remain much the same, there have been numerous landmark changes. This chapter studies the Constitution, from the perspective of the role of key figures in its development, in relation to: the sources and foundations of the Constitution in civil law; the formation and drafting of the Constitution (and the role of John Sankey in this); the structure and revision of the Constitution; its purposes and enforceable nature; and the institutional organisation of the Church in Wales. These are critically explored, where appropriate, in the context of principles of canon law common to the churches of the Anglican Communion.