The Mars warship was carrying hundreds of soldiers when it exploded in the Baltic Sea in 1564 during the Northern Seven Years’ War. 
 
 Cannons, hand grenades, and up to a thousand soldiers were on board the large Swedish warship when it exploded in the Baltic Sea, 454 years ago. 
 
 The ship, known as Mars, belonged to the Swedish navy and was one of Northern Europe’s largest and most feared naval vessels used in the Northern Seven Years’ War. 
 
 The remains were discovered at the bottom of the Baltic Sea in 2011, near to the Swedish island of Öland. 
 
 The latest discoveries from the wreckage were revealed during a press conference in Öland. 
 
 “This year, we have come closer to the people aboard. We found more skeletal parts, including a femur with trauma around the knee which we believe to stem from a sharp-edged weapon,” says maritime archaeologist Rolf Fabricius Warming, who is one of the researchers involved in the investigation. 
 
 “We also found large guns and a hand grenade. We can see from the wreckage that it was a very intense and tough battle. Between 800 and 1,000 men were on board. That is comparable to the population of an entire medium-sized town at the time. Most of them died in the explosion or when the ship sank into the watery depths,” he says. 
 
 Read More: Researchers discover remains of sunken Swedish warship 
 
 The ship contained silver treasure 
 
 Researchers had previously discovered silver treasure among the Mars wreckage. This time, one of the most spectacular finds was a large grapnel (grappling hook) an anchor-like hook, which hung from the bowsprits of warships and was used to cling onto another ships in order to board it. 
 
 Grapnels are illustrated in historical sources from the 16th century, but no actual surviving examples are known apart from this particular one, says Warming. 
 
 “It’s totally unique. Together with other exciting finds, it can shed new light on Medieval and Early Modern naval warfare. ,” he says, and adds that the divers also found remains of possible arms and armour, including helmets and swords. 
 
 Read More: The Viking’s grave and the sunken ship 
 
 Danish and Lübeckian soldiers were on board 
 
 Mars sunk due to a gunpowder explosion at the front of the ship. But shortly before, it had been under attack by Danish and Lübeckian warships according to written sources. 
 
 “Soldiers fought with hand grenades, lances, and spears, which they threw down from the masts. The fighting was structured and carefully calculated but an absolute ruckus” says Warming. 
 
 Danish soldiers, allied with soldiers from Lübeck, managed to defeat the Swedish crew and capture the warship. When the ship exploded and sank, it had three to four hundred Dano-Lübeckian soldiers aboard. 
 
 A 3D- model of the shipwreck. (Video: Ocean Discovery / Ingemar Lundgren) 
 
 A Swedish change of tactics 
 
 The new examination of the Mars shipwreck provides new insights into the events that took place between Denmark and Sweden during the Northern Seven Years’ War between 1563 and 1570. 
 
 They have documented a change in Swedish tactics from a focus on close quarter combat to long distance fighting, as indicated by large cannons up to 4.8 metres long. 
 
 Despite the large cannons, the Swedish crew did not manage to avoid engaging in close quarter combat with their enemies. The soldiers aboard were positioned underneath a net that covered the deck and was designed to prevent the enemy from jumping on board – a so-called anti-boarding net. 
 
 “We know about the use of anti-boarding nets in this battle from richly detailed written sources. The Swedish Admiral, Jacob Bagge, describes in his own account of the battle how he was injured in the shoulder by a javelin thrown from one of the fighting tops of the enemy ships. t. We are told he became furious and began shooting at those who had injured him with arquebuses so that they fell into the net below,” says Warming. 
 
 Read More: Medieval shipwreck hints at psychological warfare 
 
 A snapshot of a moment in time 
 
 Until 2011, historians relied on written sources for information about what happened to Mars, including letters from the Danish admiral Herluf Trolle and the Swedish admiral Jacob Bagge, and official royal documents. 
 
 But the shipwreck provides an entirely different type of documentation. 
 
 “There’s some ‘fake news’ in the written sources. Many people wanted to claim the honour of defeating the Mars for various political reasons. But when we study the wreckage itself we see a large congruency between the wreck site and the historical sources. One of the most striking observations was that it really was sunk by a large explosion. It was so violent that the front of the ship lies 40 metres away from the other remains,” says Warming. 
 
 For maritime archaeologist Mikkel Thomsen from the Viking Ship Museum, Denmark, looking at the well preserved, and complete remains captures a snapshot of a moment in time. 
 
 “You really feel that you’re in the killing fields,” says Thomsen, who was not involved in the study. 
 
 “The wreckage gives a snapshot of a piece of military and political history. It’s also an international history as the Seven Years’ War was fought across national boundaries,” he says. 
 
 Read More: Historic shipwrecks could be preserved in the Antarctic 
 
 Divers filmed the shipwreck 
 
 The Mars remains lay 70 metres beneath the surface of the Baltic Sea—so deep that researchers could not go down themselves to investigate. Instead, professional divers and ROVs were deployed to film the wreck. 
 
 The footage and recordings were used to create 3D-models of the wreck and the artefacts found on the site. 
 
 Scientists and divers have not been granted permission to touch or remove anything from the wreck or nearby, which might be for the best, according to Thomsen. 
 
 “The Baltic Sea has extremely good preservation conditions. The water is low in oxygen, cold, and fresh. So boring worms that are usually the greatest threat to wood cannot live there,” says Thomsen. 
 
 Lifting the remains out of the water would lead to breakdown and damage of the materials, he says. 
 
 “Moreover, it would be very difficult and extremely expensive to retrieve it from such deep water,” says Thomsen. 
 
 The exploration of Mars was carried out by researchers from the Marine Research Institute MARIS at Södertörn University in Sweden, and divers from the diving organization GUE, Västervik Museum, Ocean Discovery, and MMT. 
 
 Fifteen divers and ten researchers have participated in the latest exploration of the ship. 
 
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 Read the original article in Danish at Videnskab.dk ||||| Brett Seymour, EUA/WHOI/ARGO 
 
 Hannes Schroeder snaps on two pairs of blue latex gloves, then wipes his hands with a solution of bleach. In front of him is a large Tupperware box full of plastic bags that each contain sea water and a piece of red-stained bone. He lifts one out and inspects its contents as several archaeologists hover behind, waiting for his verdict. They’re hoping he can pull off a feat never attempted before — DNA analysis on someone who has been under the sea for 2,000 years. 
 
 Through the window, sunlight sparkles on cobalt water. The researchers are on the tiny Greek island of Antikythera, a 10-minute boat ride from the wreckage of a 2,000-year-old merchant ship. Discovered by sponge divers in 1900, the wreck was the first ever investigated by archaeologists. Its most famous bounty to date has been a surprisingly sophisticated clockwork device that modelled the motions of the Sun, Moon and planets in the sky — dubbed1 the ‘Antikythera mechanism’. 
 
 But on 31 August this year, investigators made another groundbreaking discovery: a human skeleton, buried under around half a metre of pottery sherds and sand. “We’re thrilled,” says Brendan Foley, an underwater archaeologist at Woods Hole Oceanographic Institution in Massachusetts, and co-director of the excavations team. “We don’t know of anything else like it.” 
 
 Brett Seymour, EUA/WHOI/ARGO 
 
 Within days of the find, Foley invited Schroeder, an expert in ancient-DNA analysis from the Natural History Museum of Denmark in Copenhagen, to assess whether genetic material might be extracted from the bones. On his way to Antikythera, Schroeder was doubtful. But as he removes the bones from their bags he is pleasantly surprised. The material is a little chalky, but overall looks well preserved. “It doesn’t look like bone that’s 2,000 years old,” he says. Then, sifting through several large pieces of skull, he finds both petrous bones — dense nuggets behind the ear that preserve DNA better than other parts of the skeleton or the teeth. “It’s amazing you guys found that,” Schroeder says. “If there’s any DNA, then from what we know, it’ll be there.” 
 
 Schroeder agrees to go ahead with DNA extraction when permission is granted by the Greek authorities. It would take about a week to find out whether the sample contains any DNA, he says: then perhaps a couple of months to sequence it and analyse the results. 
 
 For Schroeder, the discovery gives him the chance to push the boundaries of ancient-DNA studies. So far, most have been conducted on samples from cold climates such as northern Europe. “I’ve been trying to push the application of ancient DNA into environments where people don’t usually look for DNA,” he says. (He was part of a team that last year published the first Mediterranean ancient genome, of a Neolithic individual from Spain2.) 
 
 Foley and the archaeologists, meanwhile, are elated by the chance to learn more about the people on board the first-century bc ship, which carried luxury items from the eastern Mediterranean, probably intended for wealthy buyers in Rome. 
 
 Rare discovery 
 
 The skeleton discovery is a rare find, agrees Mark Dunkley, an underwater archaeologist from the London-based heritage organization Historic England. Unless covered by sediment or otherwise protected, the bodies of shipwreck victims are usually swept away and decay, or are eaten by fish. Complete skeletons have been recovered from younger ships, such as the sixteenth-century English warship the Mary Rose and the seventeenth-century Vasa in Sweden. Both sank in mud, close to port. But “the farther you go back, the rarer it is”, says Dunkley. 
 
 Only a handful of examples of human remains have been found on ancient wrecks, says archaeologist Dimitris Kourkoumelis of the Greek Ephorate of Underwater Antiquities, who collaborates with Foley. They include a skull found inside a Roman soldier’s helmet near Sardinia, and a skeleton reportedly discovered inside a sunken sarcophagus near the Greek island of Syrna (although the bones disappeared before the find could be confirmed). 
 
 Michael Tsimperopoulos, EUA/WHOI/ARGO 
 
 In fact, the best-documented example is the Antikythera wreck itself: scattered bones were found by the French marine explorer Jacques Cousteau, who excavated here in 1976. Argyro Nafplioti, an osteoarchaeologist at the University of Cambridge, UK, concluded that the remains came from at least four individuals, including a young man, a woman and a teenager of unknown sex3. 
 
 At the wreck site, only broken pots now remain on the sea floor — the sponge divers recovered all artefacts visible on the seabed in 1900–01. But Foley thinks that much of the ship’s cargo may be buried under the sediment. His team, including expert technical divers and members of the Greek archaeological service, relocated and mapped the 50-metre-deep site before beginning their own excavations in 2014. They have found items such as wine jars, glassware, two bronze spears from statues, gold jewellery and table jugs used by the crew (see ‘Ancient bounty’). The divers have also recovered ship components including enormous anchors and a teardrop-shaped lead weight, found in June, that may be the first known example of what ancient texts describe as a ‘war dolphin’ — a defensive weapon carried by merchant vessels to smash hostile ships. 
 
 Source: Stefan Williams, Australian Centre for Field Robotics; Alex Tourtas, EUA/WHOI/ARGO 
 
 The skeleton uncovered in August consists of a partial skull with three teeth, two arm bones, several rib pieces and two femurs, all apparently from the same person. Foley’s team plans further excavations to see whether more bones are still under the sand. 
 
 That so many individuals have been found at Antikythera — when most wrecks yield none — may be partly because few other wrecks have been as exhaustively investigated. But the researchers think it also reveals something about how the ship sank. This was a huge vessel for its time, perhaps more than 40 metres long, says Foley, with multiple decks and many people on board. The wreck is close to shore, at the foot of the island’s steep cliffs. He concludes that a storm smashed the ship against the rocks so that it broke up and sank before people had a chance to react. “We think it was such a violent wrecking event, people got trapped below decks.” 
 
 Mediterranean mystery 
 
 Michael Tsimperopoulos, EUA/WHOI/ARGO 
 
 The individuals found at Antikythera could be from the crew, which would probably have consisted of 15–20 people on a ship this size. Greek and Roman merchant ships also commonly carried passengers, and sometimes slaves. One reason people get trapped inside shipwrecks is if they are chained, points out Dunkley. “The crew would be able to get off relatively fast. Those shackled would have no opportunity to escape.” Intriguingly, the recently discovered bones were surrounded by corroded iron objects, so far unidentified; the iron oxide has stained the bones amber red. 
 
 Schroeder says that because ancient underwater remains are so rare, DNA analysis on such samples using state-of-the-art techniques has barely been tried. (Analyses were conducted on skeletons from the Mary Rose and the Vasa, but specialists no longer see those methods — based on amplifying DNA using a method called PCR — as reliable, because it is too difficult to distinguish ancient DNA from modern contamination.) Exceptions include analyses on 8,000-year-old wheat from a submerged site off the English coast (although these results have been questioned because the DNA did not show the expected age-related damage4), and mitochondrial DNA from a 12,000-year-old skeleton found in a freshwater sinkhole in Mexico5. 
 
 Anthony Ayiomamitis 
 
 Finding undisturbed remains such as those at Antikythera is crucial because it offers the opportunity to extract any DNA in the best possible condition. Previously salvaged bones are not ideal for analysis because they have often been washed, treated with conservation mater­ials or kept in warm conditions (all of which can destroy fragile DNA), or handled in a way that contaminates them. 
 
 Schroeder guesses from the skeleton’s fairly robust femur and unworn teeth that the individual was a young man. As well as confirming the person’s gender, DNA from the Antikythera bones could provide information about characteristics from hair and eye colour to ancestry and geographic origin. In the past few years, modern genome sequences have revealed that genetic variation in populations mirrors geography, says Schroeder. He and others are now starting to look at how ancient individuals fit on that map, to reconstruct past population movements. Would the shipwreck victim look more Greek-Italian or Near Eastern, he wonders? 
 
 Over dinner, the researchers decide to nickname the bones’ owner Pamphilos, after a name found neatly scratched on a wine cup from the wreck. “Your mind starts spinning,” says Schroeder. “Who were those people who crossed the Mediterranean 2,000 years ago? Maybe one of them was the astronomer who owned the mechanism.”
– Seven years after it was found, a 454-year-old shipwreck in the Baltic Sea is still revealing its treasures. Cannons, a hand grenade, possible remains of helmets and swords, and a large grappling hook used to rein in enemy ships are among recent discoveries aboard Mars, a Swedish warship that sank following a battle in 1564 with Danish and German soldiers, reports National Geographic. The battle was "an absolute ruckus," as archaeologist Rolf Fabricius Warming puts it to ScienceNordic, describing grenades, lances, and spears hurled from the tops of enemy ships at Mars. The vessel had an anti-boarding net, but as many as 400 enemy soldiers were among the 800 to 1,000 on board when a gunpowder explosion at Mars' bow sent it to rest 250 feet below the sea's surface near Öland. "It was so violent that the front of the ship lies [130 feet] away from the other remains," says Warming, noting any soldiers not killed in the explosion would have drowned. In the latest search of the untouched wreck by divers and underwater vehicles, "we have come closer to the people aboard," he adds. "We found more skeletal parts, including a femur with trauma around the knee which we believe to stem from a sharp-edged weapon." But it's the grappling hook Warming finds most exciting. He calls it "totally unique," noting no other examples from the 16th century exist, except in illustrations. The hook will remain where it lies, however, along with silver treasure previously found. Researchers haven't been granted permission to disturb the wreck, which lies in cold, low-oxygen water ideal for preserving wood. (Legend has it the ship was cursed.)