The hundreds of Shropshire were greatly reformed throughout the 12th century, and one of the earliest changes to be made was the formation of Munslow. During the reign of Henry I (1100 to 1135) the hundreds of Culvestan and Patton were formally merged (having been paired by a common caput for some time) and the new hundred formed was named Munslow. The new hundred included most of the manors of Culvestan (not Huntington, which went to Stottesdon) and Patton (not Madeley or Beckbury, both which went to Brimstree — nor Acton, which went to Stottesdon). In addition a number of manors from the hundred of Leintwardine (which was being dissolved) were transferred, with a boundary between the new hundreds of Munslow and Purslow taken to be the Roman road running from Wistanstow south to the Herefordshire border (and explains why Rowton and Shelderton were in different hundreds to the rest of their respective parishes). Also brought into Munslow was a part of the parish of Richard's Castle, causing a division between Shropshire and Herefordshire there that still exists.
