Christ Pantokrator

In medieval iconography Pantokrator (Almighty) is one of Christ's many attributes.

The oldest representation in St. Catherine's Monastery, Sinai. 

Note the two different facial expressions which suggest Christ double nature: 

human and divine.

The Dome of the Holy Sepulchre, 

Jerusalem

Church of Daphni Monastery (12th c.)

Mosaic from Cefalu Cathedral, Sicily