 It was once thought that this monetary co-operation was reflected in a unique penny bearing the name of Æthelwulf on one face and that of Berhtwulf on the other.However, this coin more likely represents an unofficial production without any particular political significance.The recovery of Mercian minting was made most manifest by the adoption in Wessex of the 'lunettes' type first struck at London by Berhtwulf's successor Burgred.