The union between Wales and England was formed in 1535 when the two nations became a single state. In the late nineteenth century, political demands for Welsh autonomy began to circulate, led by the Liberals and later Plaid Cymru. In response, the UK Government began to transfer some administrative control to ‘Welsh departments’ within the Board of Education (1909) and the Ministry of Agriculture (1919). By 1940, the Welsh Board of Health had taken over responsibility for housing, water and other local government services.
In 1964, the first Secretary of State for Wales was appointed, and the Welsh Office was created the following year with offices in Cardiff and Whitehall. Initially, the Welsh Office had control over town planning, housing, water and sewerage, local government, roads and some aspects of economic planning. The Welsh Secretary also had oversight within Wales of the execution of policy set by the UK Government including health and education. Over time, its remit expanded.