 Major excavations beginning with C. A. Ralegh Radford's work in the 1930s on and around the site of the 12th-century castle have revealed that Tintagel headland was the site of either a high status Celtic monastery (according to Ralegh Radford) or a princely fortress as well as trading settlement dating to the 5th and 6th centuries (according to later excavators), in the period immediately following the withdrawal of the Romans from Britain.Finds of Mediterranean oil and wine jars show that Sub-Roman Britain was not the isolated outpost it was previously considered to be, for an extensive trade in high-value goods was taking place at the time with the Mediterranean region.Finds from the excavations are preserved at the Royal Cornwall Museum in Truro.