In a lot of the Christian churches, shrines, and so on that were converted by the Seljuks and the Ottomans, they took great pains to deface (literally) the icons and frescoes.
When you go in and look at many of them, you’d see this happening up to the level that the Seljuk/Ottoman soldiers could reach with their spears.
I saw that all over the place, but it was particularly noticeable in the cave churches in Cappadocia.
Defiled!