Among the documentary source of the Gabinet Numismàtic de Catalunya are preserved some of Paradaltas' coinage plates. The majority come from known works. Of this grouping it has been possible to assemble six with identical characteristic forms. One of them has been able to be identified as Plate I of the Tratado de Monedas published by Paradaltas en 1847. The other five present, in part, identical formal characteristics of the former impression in spite of having, instead, numbering correlated with different typography and not appearing in the cited edition. Nor do they come from any other catalogued work. So, what is the mystery of these extraordinary plates?

An announcement that appeared in the press in 1847, in which was promulgated the subscription of a book in two volumes that Paradaltas would publish imminently, brings about the solution to this unknown. The first part of the work published coincided with the printing of the Tratado of 1847, already cited. But on the other hand, the second part was meant to be an ambitious handbook that intended to put together, in fifty plates, coins coming from the entire world, with their principal characteristics. This book did not come to be published, despite the cited announcement saying that some plates had already been engraved. These last plates are, without doubt, those that now are identified and presented for the first time as the unique pieces that they are!