cella, in Classical architecture, the body of a temple (as distinct from the portico) in which the image of the deity is housed. In early Greek and Roman architecture it was a simple room, usually rectangular, with the entrance at one end and with the side walls often being extended to form a porch. In larger temples, where the cella is open to the sky, a small temple was sometimes placed within. In the Byzantine architectural tradition the naos was preserved as the area of a centrally planned church, including the core and the sanctuary, where the liturgy is performed.