 Later in Offa's reign there was a second reform in which the weight was raised, the size of the flan increased and a common non-portrait design introduced at all three mints.This 'heavy coinage' can be closely dated, for no examples of it are known in the name of Archbishop Iænberht, whilst there are no 'light' (i.e., pre-reform) pennies of Archbishop Æthelheard, indicating that the reform took place in 792 or 3.The coins of Offa provide valuable evidence for a new dimension of royal authority and action with regard to the coinage, and have received much attention from historians because of their impressive imagery and range of royal titulature