It was the first stop on an extraordinary journey. On a bright but bitterly cold January afternoon earlier this year, I found myself on a small island in the Black Sea, just off Sozopol on the east coast of Bulgaria.
Sveti Ivan has long been a destination for travellers: it boasted a temple of Apollo in ancient times. But I was there to speak to an old Bulgarian archaeologist about the most important find of his career.
In 2010, Kasimir Popkonstantinov discovered what he believes are the bones of one of the most famous of all saints: John the Baptist. I was interested in what DNA analysis could tell us about these bones, and other ones.
Together with biblical scholar Joe Basile, I was travelling around the world filming a documentary about the religious and scientific evidence linking archaeological artefacts to Jesus Christ himself.
Popkonstantinov made his discovery when excavating a sixth century church on the island, built on top of a basilica from the century before.
As he carefully scraped through the mud where the altar would have been, he came across a stone slab and was amazed to find a small marble box underneath. He immediately knew what it was.
For a church to be consecrated in this part of Europe in the fifth century, it needed to contain a relic from a holy saint or religious person. This box, known as a reliquary, would have housed such a relic.
He continued to dig around and found another, smaller box about a metre away. On the edge of the inferior box was an inscription: "May God save you, servant Thomas. To Saint John".