 Chadwick attempted to allocate each tribe to one or more English shires, with the use of key passages from historical texts.In 1971, Hart attempted a "complete reconstruction of the political geography of Saxon England at the end of the 8th century".Assuming that all the English south of the Humber are listed within the Tribal Hidage, he produced a map that divides southern England into Mercia's provinces and outlying dependencies, using evidence from river boundaries and other topographical features, place-names and historical borders.