In Wales, a Celtic system of division called cantrefi (a hundred farmsteads) had existed for centuries and was of particular importance in the administration of the Welsh law. Following the Laws in Wales Acts 1535 and 1542, Wales was divided into a similar system of hundreds to be aligned with England.
Wales was divided into hundreds following the Laws in Wales Acts 1535 and 1542. This resulted in the creation of five new counties (Monmouthshire, Brecknockshire, Radnorshire, Montgomeryshire and Denbighshire) from the Marches of Wales. Combined with the transformation of the Lordships of Pembroke and Glamorgan into new counties, with the existing counties of Cardiganshire, Caernarfonshire and Flintshire (created by the Statute of Rhuddlan) this gave Wales thirteen counties.