A Turkish official says restoration workers have uncovered the never-before-seen mosaic face of an angel at Istanbul's Haghia Sophia — a former Byzantine cathedral.

The cathedral's Christian mosaics were covered up in line with Muslim custom shortly after Constantinople — the former name for Istanbul — fell to the Ottomans in 1453 and the cathedral was turned into a mosque.

Some of the mosaics were revealed after it was turned into a museum in 1935, but the angel image remained covered.

Ahmet Emre Bilgili, the head of culture and tourism affairs for Istanbul, told the Associated Press on Friday that restoration workers will now work to uncover a second mosaic angel image.

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