This sheet is one of Piranesi’s latest architectural fantasies, for after the mid-1760s he would largely abandon such exercises in imaginary spaces and would concentrate instead on archaeological study and classicizing designs. On the one hand, we can see how a study like this Fantasy of a Magnificent Forum looks back to his earlier architectural drawings, with its creative combination of a triumphal arch and a colonnaded forum, ideas that we can see in many earlier works. On the other hand, we see how far Piranesi has come as a draftsman, for this study is apparently drawn freehand, with no careful preliminary perspective drawing made with a ruler and black chalk. The bold lines and jagged hatching suggest instead that it was thrown off in a fury of invention. It may in fact have been done as a sort of command performance, for a similar drawing at the National Gallery of Art has an inscription indicating that it was drawn “in the presence” of a young English visitor to Piranesi’s studio. We can imagine this drawing was created in similar circumstances, as an end in itself, the outpouring of a mind filled with grand architectural visions, the very epitome of Piranesi’s “sublime ideas.”