No. Perhaps fortunately, few medieval kings were mad enough to try that, and the ones that were mad enough were not rich enough to do it.
Following the Spanish conquests in Latin America and the Portuguese forays in the Spice Islands of the East, Spain and Portugal became extraordinarily rich. The result of this relatively sudden wealth, however, was hyper-inflation in Western Europe. This ruined the economies of Portugal and Spain, a devastating effect that has lasted almost to the present.
Castles of gold with foundations of lead?