“Of the work in crystal… I should like to mention the author, just as I should like to inform you of the nature and origin of this form of painting. But I have not been able to discover who painted it, nor how it was that painting on crystal first started”, writes the Cardinal in his Musaeum. We do not know if this painting on glass is the one described by Federico, but we can say that art historians today have identified it as the work of the great Dutch artist Lucas van Leyden. The work shows the young David, accompanied by the chants of women, as he carries the head of Goliath, stuck onto his own enormous sword, in triumph. The story of the duel between David and Goliath appears in the First Book of Samuel (Sam 1:17).