coins were heavier, broader and thinner than the pennies they replaced, and were prompted by the contemporary Carolingian currency reforms. The new pennies almost invariably carried both Offa's name and the name of the moneyer from whose mint the coins came. The reform in the coinage appears to have extended beyond Offa's own mints: the kings of East Anglia, Kent and Wessex all produced coins of the new heavier weight in this period. Some coins from Offa's reign bear the names of the archbishops of Canterbury, Jænberht and, after 792, Æthelheard. Jænberht's coins all belong to the light coinage, rather than the later medium coinage. There is also evidence that coins were issued by Eadberht, who was Bishop of London in the 780s and possibly before. Offa's dispute with Jænberht may have led him to allow Eadberht coining rights, which may then have been revoked when the see of Lichfield was elevated to an archbishopric. The medium-weight coins often carry designs of high artistic quality, exceeding that of the contemporary Frankish currency. Coin portraits of Offa have been described as "showing a delicacy of execution which is unique in the whole history of the Anglo-Saxon coinage". The depictions of Offa on the coins include a "striking and elegant" portrait showing him with his hair in voluminous curls, and another where he wears a fringe and tight curls. Some coins show him wearing a necklace with a pendant. The variety of these depictions implies that Offa's die-cutters were able to draw on varied artistic sources for their inspiration. Offa's wife Cynethryth was the only Anglo-Saxon queen ever named or portrayed on coinage, in a remarkable series of pennies struck by the moneyer Eoba. These were probably derived from contemporary coins from the reign of the Byzantine emperor Constantine VI, who minted a series showing a portrait of his mother, the later Empress Irene, though the Byzantine coins show a frontal bust of Irene rather than a profile, and so cannot have been a direct model. Around the time of Jænberht's death and replacement with Æthelheard in 792–93, the silver currency was reformed a second time: in this "heavy coinage" the weight of the pennies was increased again, and a standardised non-portrait design was introduced at all mints. None of Jænberht's or Cynethryth's coins occur in this coinage, whereas all of Æthelheard's coins are of the new, heavier weight. There are also