Modern-day Aldborough, in North Yorkshire, lies on the site of Isurium Brigantum, the former administrative capital of the Brigantes, one of the largest indigenous tribes of Roman Britain. Strategically located on Dere Street, by the second century AD it had become a key Roman town engaged with the supply of the northern frontier, with buildings and mosaics that reveal a thriving economy through to the fourth century.In the eighteenth and nineteenth centuries, the site of Isurium Brigantum was the subject of important antiquarian investigations. However, unlike some southern counterparts – for example, Calleva Atrebatum or Verulamium – in the twentieth century it attracted less archaeological attention until, in 2009, a team of archaeologists led by Dr Rose Ferraby and Professor Martin Millett began a major re-examination of the site. Large-scale geophysical surveys using both gradiometry and high-resolution ground-penetrating radar were conducted and these revealed most of the town and its surroundings, allowing its development from the second century AD to the medieval period to be mapped with great accuracy.