It was of strategic importance in medieval Wales as the location of the main seat of the princes of Deheubarth at Dinefwr.
Cantref Mawr was an upland area, bounded by the rivers Tywi, Teifi and Gwili.
The area at this period was covered in dense scrub which caused difficulties for invading armies, so that the Cantref Mawr often provided a secure refuge for the princes of Deheubarth when facing an invasion.
(1911) The history of Wales from the earliest times to the Edwardian conquest (Longman, Green & Co.)
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