Typically for the time, it was a large timber gate with a forecourt where missiles could be discharged from three sides against enemies. Thanks to the high water table the bottom of the gate posts was still preserved. Under difficult conditions, constantly scooping and pumping out water, the dedicated team members were able to recover them intact. To our delight the bark was preserved. We knew that we would probably obtain a precise felling date.
Tree rings vary in width from year to year, depending on temperature and the amount of rainfall.
Excitement grew on 19 January when Ian Tyers, an expert on tree-ring dating at the University of Sheffield s Department of Archaeology was able to date two of the three posts to between October AD 44 and March AD 45. It is believed that these are the earliest Roman timbers in Britain to be dated, and the felling dates almost certainly indicate the date the fortress was built. Knowledge of the Roman army's customs further narrow the date to the autumn of AD44. Dr Sauer explained the importance of the find. Roman control over the Midlands was firm enough for the army to build a permanent base in Oxfordshire.