Within the great Justinianic fortress-monastery of St. Catherine at the foot of Mount Sinai — built by the Byzantine Emperor Justinian I between 548 and 565 — is preserved the oldest surviving panel icon of Christ in the Christian tradition: a 6th-century encaustic painting on wood, approximately 84 × 45 cm, of Christ Pantocrator (Almighty Ruler).
The icon survived the iconoclasm of the 8th–9th centuries only because Sinai was outside imperial control. It has been preserved continuously in the monastery treasury since. The famous asymmetry of the face — when each half is mirrored to itself, one Christ-face is serene and merciful (right) and the other in stern judgement (left) — has shaped the entire subsequent tradition of Christ Pantocrator iconography. The icon was 'rediscovered' for the Western art-historical world by the 1958 photographic expedition of Princeton scholar Kurt Weitzmann. St. Catherine's Monastery itself is the oldest continuously inhabited Christian monastery in the world and a UNESCO World Heritage Site.