German architect Johann Michael Knapp published the first volume of his book on early Christian architecture in 1822. The 'Christian Basilicas of Rome' contains 50 images made using 'kupfertafeln' or copperplates, equivalent to the British technique of engraving. This is a drawing made for the kupfertafeln process.

Like Palladio did with the Baths of Caracalla|, Knapp is liberally employing his imagination and in this rendering of San Clemente he has stripped the basilica back to its Romanesque core. The detail of the mosaic - or Cosmati - floor is particularly exceptional. The mosaic is an ideal subject for engraving as the technique lends itself to constructing patterns out of lines spaced closely together.