A shipwreck discovered in the murky waters of the Baltic Sea is believed to be a legendary 17th century warship whose captain went down with it in battle rather than surrender to the enemy.

Deep Sea Productions, an underwater research team, said Wednesday it believes the 25-meter (82-feet) wooden wreck it found off the island of Oland this summer is the ship Svardet, which sank when Sweden was defeated by a Danish-Dutch fleet in a 1676 naval battle.

Malcolm Dixelius, a member of the research team, said that wood samples show the wreck is from the 17th century. He also said the stern of the ship is missing, which is consistent with historical reports that Svardet went under after a fire and explosion at the stern.

Thousands of other wrecks - from medieval vessels to warships sunk during the world wars - have been found in the Baltic Sea, which doesn't have the ship worm that destroys wooden wrecks in saltier oceans.

Marine Archaeology Professor Johan Ronnby said he is convinced the newly discovered wreck is that of Svardet, making it one of four giant warships from the 16th and 17th centuries that have been recovered in the Baltic Sea.

Earlier this year, the same research team discovered the 16th century warship Mars at a nearby location. The ship Kronan was discovered in 1981, yielding more than 30,000 archaeological artifacts.

Among the four is Sweden's most famous maritime discovery, the 17th century royal warship Vasa, which was raised from the seabed in the Stockholm harbor in 1961 and can be viewed in a popular museum.

Svardet and Kronan were lost in the same fight, described as the largest naval battle in the history of the Baltic Sea.

According to historical reports, Svardet was set afire by a Dutch ship after a five-hour battle. The commander, admiral Claes Uggla, refused to abandon his ship as it went down.

The research team had been searching for Svardet for more than 10 years when it found it between the Swedish islands Gotland and Oland at a depth of between 50 and 100 meters, surrounded by the hundreds of canons it carried when it went under.

The team will now collaborate with researchers at the Swedish Maritime Archaeological Research Institute to document the shipwrecks and make a 3D documentary about the vessels.