Thinking about defaced sculptures again
Iconoclasm is the destruction of statues paintings or symbols due to political or, like in this case, religious reasons.
The christians that made this probably view these statues as pagan idolatry or even as the worship of demons, as christians conflated the greek concept of daimons with their own undertanding of evil spirits.
I think it's sad we will never know how this bust looked like before being defaced.
Another more recent example of this practice is this huge Buddha that once existed in Afganistan.













