Ancient Roman mosaic, depicting a skeleton (perhaps a memento mori) above the Greek maxim from Delphi γνῶθι σεαυτόν (”know thyself”).  Artist unknown; 1st cent. CE (?)  Found during excavations at the convent of San Gregorio on the Via Appia, Rome; now in the National Museum, Rome.  Photo credit: Lessing Photo Archive.

Pallas Athena/Minerva with her aegis.  Roman mosaic (3rd cent. CE), surrounded by a modern (18th century) mosaic depicting celestial bodies and geometrical patterns.  Now in the Museo Pio-Clementino, Vatican City.