Caesar Augustus or Octavian (left) is often considered the first Roman emperor. He ruled between 27 BC and AD 14 and initiated the "peace of Rome." His name appears in Luke's account of the birth of Christ (read here). He was a shrewd and able politician who used traditional Roman religion to his advantage and was himself known as "Savior" and the "Son of God."
Livia (right), was already mother to future emperor Tiberias and pregnant with a second child when she met Octavian. Octavian fell in love with her immediately. Tradition has not been kind to her however. She is remembered as an unsavory character, responsible for poisoning more than a few friends and relatives (and possibly Augustus himself!).
These images of both Augustus and Livia were found amid the rubble of Ephesus. Their statues were likely "Christianized" and broken during the Early Byzantine Era. When found, crosses were carved into their foreheads. The practice is not unique. Is it wishful thinking on the part of Christians, an act of purification, exorcism, or something else?
You can find these artifacts as I did in the Ephesus Archaeological Museum in Selcuk, Turkey.
For more on cross-marks, see T. M. Kristensen and L. Stirling, The Afterlife of Greek and Roman Sculpture: Late Antique Responses and Practices (University of Michigan, 2016): 145-146.