Some scholars, such as Alan Stahl, have looked back at descriptions of the coins by later writers, and comes to the conclusion that even though Leonello and Pisanello crafted and designed the coins to look like the currency of Roman antiquity, their makeup and metal were very much medieval. Stahl also mentions that the replication process were developed about a century after Leonello's death, so even though Pisanello's coins were for Leonello - according to Alan - it was the beginning of the development for replication within Ferrara, which would develop in the following centuries.