I wonder what is this?

Selon? Sılon? silow??
This is the postern door of a church, Ayios Costantinos; in Istanbul city / Beykoz town.

You may think it means nothing. I don't know what it means but maybe with a good English or Greek, or maybe Armenian somebody can find anything.
SILON ? The second letter not an I. Maybe a different alphabet.
The thing makes it important for me that, this is a church in a district famous with "Pastor magic". Although the church is not neglected, at least seem normal from far, but this writing stay there. How can it stay there, if the pastor in church does aware of it? So he has to aware of this writing, has not he?
So why did not the pastor erase this writing?
What are these writings mean?
And many crazy questions in my mind...