This chapter provides an outline of developments in the Church in Wales since 1920. It seeks to place the specialised chapters which follow in their broader ecclesial context. The study uses the tried and tested technique of periodisation as a convenient way of approaching the subjects treated. The landmark developments in the first period (1920-1945) include the creation of the administration of the Church, forming new dioceses, and establishing sound ecclesiastical finances. The second period (1946-1970) is one of greater self-confidence in the Church, with modest liturgical development and ecumenical cooperation. The third period (1971-1995) is characterised by liturgical innovation and greater ecumenical progress, the ordination of female deacons, but also an increasing reduction in clergy numbers. The final period (1996-2020) is one of rapid change, including the ordination of female priests and bishops, a reorganisation of parochial structures, and a severe decline in Church membership.