Upon entering a Byzantine Catholic church, one’s gaze is normally drawn first to the iconostasis, or icon screen, that appears to separate the sacred space of the altar from the nave, or main worship space. It is the most prominent internal architectural feature of a Byzantine church. There will be some variance in style and composition, but there are certain essentials that are always present – Catholic or Orthodox.
Essentially, the iconostasis is a screen covering the opening of the sacred space, the altar or “holy place.” There are three doors and four icon panels at a minimum on the “local row,” the level closest to the people. An icon screen can have up to three other levels, depending upon the space available and other resources. It developed historically from the chancel wall in synagogues, which also served the function to separate the holy place from the gathering space of the people. In churches of the Roman tradition, the chancel wall evolved into the communion rail. In Byzantine Churches, efforts to decorate the church led to this form of artistic expression, but always first following the theological function before adding artistic form.