Final answer:
The sanctuary space surrounding the altar of an eastern church is known as the bema, separated from the naos by a templon, which evolved into the iconostasis featuring religious icons.
Step-by-step explanation:
The sanctuary space surrounding the altar of an eastern church is known as the bema. This space is where the clergy would celebrate the Eucharist. In Byzantine architecture, the bema was separated from the naos, where most worshippers stood, by a templon. The templon could consist of chancel slabs, colonnettes, and an epistyle or templon beam, which was widespread in Byzantium and allowed laypeople to see into the bema. Over time, this developed into the iconostasis, which incorporated intercolumnar icons that characterized Eastern Orthodox church sanctuaries.
In early Christian and Byzantine art, these sacral spaces were often lavishly decorated with mosaics and frescoes that had religious significance, symbolizing the rituality and sacredness of the actions performed within. Figures and scenes depicted in the space of the bema were chosen to reflect the liturgical functions, such as saints and biblical events, rendered against backgrounds that evoke the ethereal space of the divine.