Final answer:
In early Christian or Byzantine churches, the narthex was a portico or vestibule before the nave where non-christened individuals could gather. It contained religious art and served practical purposes.
Step-by-step explanation:
In early Christian or Byzantine churches, the portico or vestibule before the nave was known as the narthex.
The narthex served as an entrance area where people who had not yet been christened could gather and observe the church service. It was a transition space between the outside world and the sacred space of the church.
The narthex often contained mosaics or frescoes depicting religious scenes or figures, providing visual instruction and inspiration for the worshippers.
It also served practical purposes, such as storing liturgical items and maintaining order during the service.
An example of a narthex can be seen in the southwest vestibule of Hagia Sophia, where a mosaic of emperors from centuries past was installed.