Polychrome glass, glass rods, plaster of Paris, iron, wax; pulled, cut, assembled, embedded. Micromosaic panel in a carved gilt wood frame; made of minute glass tesserae (smalti filati), showing a view of St. Peter's Square in Rome at the time of a Sunday benediction of Pope Leo XIII. The Pope can be seen in the background standing on the balcony blessing a large gathering of pilgrims; in the foreground promenade elegantly dressed figures. A panel with this design was commissioned by the Pecci family in 1879 from the master mosaicist Biagio P. Barzotti at the Vatican Mosaic Workshops; the panel is signed in the lower left corner "B.P. Barzotti, R.F.S.P.".

The panel is a superb example of the intricate mosaic work executed by the Vatican Mosaic Workshops in the second half of the 19th century. The workshop was founded in 1576 to provide embellishments for St. Peter's cathedral. In the following centuries, Rome became reknowned for this technique throughout Europe. The Barzotti panel is a superb example of the virtuosity and technical skill of the mature micromosaics executed in the Vatican Workshop in the 19th century. There are remains of an old broken paper label on the back of the panel with a Papal seal.