The cause of this sudden explosion in the volume of currency is not clearly known. Certainly not all of them came from Manuel's silversmiths. Both Wroth and Retowski identified a number of coins minted as imitations in Georgia to meet demand there. Michel Kuršanskis has suggested some of these types were struck during the reigns of Manuel's successors—Andronikos and George—because their Mongol overlords forbade them from minting silver coins in their own names. Nevertheless, this leaves the vast majority of the coins with his name on them as being struck during his reign.