What is "proskynetarion"

A proskynetarion (Greek προσκυνητάριον (from: ''προσκύνησις) ''meaning "oratory" or "place of worship", plural proskynetaria) is a monumental icon usually of Christ, the Virgin, or the patron saint of a church. It was normally placed on the piers separating the parts of a templon in a Byzantine church. They were usually made of mosaic or fresco in a marble frame. Proskynetaria of patron saints were often in the narthex or on the nave walls.