In 1563 and 1564, Sweden built a massive warship that was the pinnacle of naval technology at the time.
Its creation ushered in a sea change in naval combat — despite the fact that the ship sank early in its first battle.
King Eric XIV of Sweden ordered that the ship Mars be constructed to put Sweden at the forefront of naval artillery. It was a five-deck ship with two decks dedicated to artillery, mostly cannons. Even the crow's nests had guns.
All this came at a time when naval engagements were decided by seamanship and armed boardings —where a group of sailors from one ship crossed to the deck of an enemy ship and fought with swords and pistols.
Naval artillery in the early and mid-1500s was focused on killing enemy personnel or causing structural damage to the enemy ship, but no one had ever sunk a ship that way. Ships were usually sank by fire, sabotage by boarding crews, or by ramming.
But Eric XIV had a vision of the future and ordered his admiral to take the Mars as part of a huge fleet aimed at Denmark and Lubeck (part of modern Germany) and sink ships using its naval artillery.
And the admiral delivered... probably. A Danish chaplain said that the Mars cast a somber shadow over the whole Danish and German fleet when it arrived. He also said it later sank the Longbark, one of the largest ships in the enemy fleet, with naval gunnery.
If accurate, it was likely the first time a ship was sunk by naval artillery.
The 64-gun warship Vasa sits in museum. The ship was built in the tradition of the Mars, but wasn't as well designed and floundered during its first voyage in 1628.
(Jorge Lascar, CC-BY 2.0)
But the Mars cast too large a shadow and, as a consequence, drew too many attackers. On the second day of the battle, enemy ships sent massive amounts of fireballs onto the Mars and disabled it before sending boarding parties onto it.
What happened next is unsure. A fire definitely occurred in the Mars' gunpowder stores, and that might have set the loaded cannons off. Regardless, the ship was destroyed in the following hours, left to sink in approximately 250 feet of water.
Luckily for archaeologists, it was 250 feet of the Baltic Sea, which lacks the large populations of shipworms that destroy wrecks in the rest of the world. And the cold water is relatively still, reducing erosion. According to researchers who spoke to National Geographic, the wreck might be the best preserved vessel of its kind.
The concept behind the Mars was proven in the years following its loss as navy after navy, including those of Denmark and Lubeck, constructed large ships reminiscent of the cannon-toting behemoth.