This is a painting depicting a historical scene, possibly a mural, that includes an older man in a green robe sitting at a wooden desk

This is a painting depicting a historical scene, possibly a mural, that includes an older man in a green robe sitting at a wooden desk. He has reddish-brown hair and a beard. He is writing with a feather quill in an open book. On the desk are other books, an inkwell, and a handbell. In the upper right corner of the painting, there's an open book with the first letters of the Cyrillic alphabet "А, Б, В, Г" written in burgundy. The book is encircled by a laurel wreath and the background behind it is yellow, likely indicating the sun. The text above the book reads "SU 'OTEC PAISIJ'". Below the laurel wreath, there is text written in Bulgarian. The painting style is somewhat archaic and illustrative. The location is Madan, Bulgaria. The setting is indoors, likely in a public building or school.