Scientists in the 1960s discovered an ancient Greek merchant vessel off the coast of northern Cyprus. They found a time capsule that was a fascinating glimpse into a crucial period of the Mediterranean after the death of Alexander The Great.

It has been difficult to determine the exact date of the Kyrenia wreck. Previous scientific dating methods have produced conclusions that are in conflict with archeological evidence. Researchers have calculated the timeline with a new level of precision, using techniques that can also be used to date other ancient wrecks.

Analyzing organic material, such as the wooden timbers of the ship, almonds in its cargo and an animal-bone gaming piece, called an "astragalus", which was used to play dice, the researchers concluded that the ship sank around 280 BC. This is slightly later than previous scientific dating estimates, but better matches the archeological evidence.

Sturt Manning of Cornell University, professor of classical archaeology and ancient maritime history, described the Kyrenia ship as an "iconic vessel from the early Hellenistic era, central to the story of ancient maritime technology."

The vessel, which was about 46 feet long (14 meters), was made of wood and covered with lead. One mast carried a square-shaped sail. It probably had a crew of 4. The ship sank approximately a mile (1,6 km) from the coast. Nearly 400 amphoras, large two-handled ceramic storage jars, were aboard. Some of them contained almonds while others held wine. There were also heavy millstones used as ballast.

The cargo, amphoras of various types, suggests that it was trading around the Aegean Sea and east Mediterranean. The main cargo consisted of amphoras of a kind associated with Rhodes, an island in the southeast Aegean, said Manning.

Researchers determined, using various lines of evidence that the ship was constructed between 345-313 BC. It sank in the period between 286-272 BC.

Alexander's death in 323 BC, which had led to the conquest of large areas of the Mediterranean and beyond, sparked regional power struggles. Cyprus was a hotly contested region between the successors to Alexander who ruled in the Aegean and those ruling in Egypt. The latter won control of the island.

In a Cyprus museum, the Kyrenia's ship remains are on display.

Archaeologists can reconstruct human history using ancient shipwrecks. Underwater sites, like the one where the Kyrenia is buried underwater, decay of archaeological materials occurs much slower. According to Brita Lorentzen, a University of Georgia professor of anthropology and co-author of the study, organic materials such as wood, rope, or seeds can be preserved much better than they would on land.

Last week, the discovery of an ancient shipwreck in deep water off Israel's coast, which dates back to 1300 BC was announced.

Ships were an important form of transport in ancient times, allowing people to travel from one location to another, build social networks and trade ideas and goods. The contents of a shipwreck can reveal which goods were traded and exchanged. They also show where people traveled by sea and which groups were in contact.

The wood of this ship was preserved on land using polyethylene glycol, a chemical compound. Radiocarbon dating was complicated by this. This technique is used to determine an object's ages based on decay of a radioactive carbon form over time.

The addition of PEG helps prevent ship timbers from drying, shrinking and becoming dust when they are removed from the water. It also contains petroleum and lots of carbon from dead organic remains," Lorentzen explained.

Researchers developed improved methods for removing PEG from timber so that radiocarbon dating can be performed. Radiocarbon dating was also done on almonds and astragalus.

The analysis of the annual growth rings of trees can also be used to date ancient wooden artifacts. Researchers found an error in the scientific standard that was used to analyze wood from this period and convert radiocarbon measurements in calendar dates in the northern hemisphere. They updated it.

Manning stated that the work is applicable to ancient shipwrecks in general.