Simplify the following text for a Grade 15 native English-speaking person.
Original: Certain artistic traditions that originated in the Byzantine Empire , particularly in regard to icon painting and church architecture , are maintained in Greece , Serbia , Bulgaria , Russia and other Eastern Orthodox countries to the present day .
Simplified: Certain traditions that originated in the Byzantine Empire , particularly in regard to icon painting and church architecture , are maintained in Greece , Russia and other Eastern Orthodox countries till now .