DEMRE, Turkey — In the fourth century A.D., a bishop named Nicholas transformed the city of Myra, on the Mediterranean coast of what is now Turkey, into a Christian capital.

Nicholas was later canonized, becoming the St. Nicholas of Christmas fame. Myra had a much unhappier fate.

After some 800 years as an important pilgrimage site in the Byzantine Empire it vanished — buried under 18 feet of mud from the rampaging Myros River. All that remained was the Church of St. Nicholas, parts of a Roman amphitheater and tombs cut into the rocky hills.

But now, 700 years later, Myra is reappearing.

Archaeologists first detected the ancient city in 2009 using ground-penetrating radar that revealed anomalies whose shape and size suggested walls and buildings. Over the next two years they excavated a small, stunning 13th-century chapel sealed in an uncanny state of preservation. Carved out of one wall is a cross that, when sunlit, beams its shape onto the altar. Inside is a vibrant fresco that is highly unusual for Turkey.