Kyrenia Ship Hull during excavation. Kyrenia Ship hull on the seabed off northern Cyprus during underwater excavation in the later 1960s.
“Kyrenia was one of the first times it was realized this type of rich evidence from the classical world could be found largely intact more than 2,000 years later on the seabed, if you could find it,” said Sturt Manning. “It was a bit of a landmark moment, the idea that you actually could dive, excavate, and bring up a classical-era ship and so discover this long-past world directly. Shipwrecks are unique time capsules, and you can get amazing preservation.
The first volume of the final publication of the Kyrenia ship project, released last year, argued the wrecking date was a little later, closer to 294-290 BCE, but the primary piece of evidence – a poorly preserved, nearly illegible coin – was not watertight. Manning’s team worked with researchers at the University of Groningen in the Netherlands to develop a new method to clean PEG out of wood, and they demonstrated it on PEG-treated Roman-era samples from Colchester, England, that already had established dendrochronological dates.
The dates showed that the most recent preserved tree rings from these timbers grew in the mid-later 4th century BCE. Because the samples did not include bark, the researchers couldn’t determine the exact date the original trees were felled, but could say the date was likely after approximately 355-291 BCE.
Manning took a closer look at the data behind the calibration curve, which has been assembled over many decades by dozens of labs and hundreds of scientists. He discovered that the period between 350 and 250 BCE had no modern accelerator mass spectrometry radiocarbon data behind it. Instead, the calibration curve in this period relied on only a few measurements conducted in the 1980s and 1990s using an older type of radiocarbon-dating technology. With collaborators in the U.S.