The History of Herefordshire starts with a shire in the time of Athelstan (895–939), and Herefordshire is mentioned in the "Anglo-Saxon Chronicle" in 1051. The first Anglo-Saxon settlers, the Magonsætan, were a sub-tribal unit of the Hwicce who occupied the Severn valley. The Magonsætan were said to be in the intervening lands between the Rivers Wye and Severn. The undulating hills of marl clay were surrounded by the Welsh mountains to the west; the Malvern Hills to the east; the Clent Hills of the Shropshire borders to the north, and the indeterminate extent of the Forest of Dean to the south. The shire name first recorded in the "Anglo-Saxon Chronicle" was derived from "Here-ford", Old English for "Army crossing", the location for the city.