see iconostasis

A templon (from Greek τέμπλον meaning "temple", plural templa) is a feature of Byzantine architecture that first appeared in Christian churches around the fifth century AD and is still found in some Eastern Christian churches. It eventually evolved into the modern iconostasis, still found in Orthodox churches today. It separates the laity in the nave from the priests preparing the sacraments at the altar.

A wooden panel extending the length of the architrave beam.