Had you been around 155 years ago, and stood on the Virginia shore on a March day in 1862, you would have witnessed the most astounding sight.

You would have glimpsed a ship the likes of which you had never seen before: what looked like a slab-sided floating butter dish sailing into Hampton Roads, Virginia on March 8, 1862. It was the Confederate States Ship Virginia, a warship built upon the wooden hull of the captured Union frigate Merrimac (by which name the ship was also known).

Wooden ships equipped with both steam engines and sails would have been a familiar sight in 1862, as the Union navy maintained its blockade of the South’s trade. But the Virginia was different: a steam-powered ship without sails, but with sides covered by four-inch-thick iron plating, and armed with ten cannon and a three-foot iron ram protruding from the bow.

It wasn’t that ironclads were totally new: Britain and France had already been building ironclads (the first ironclad, the French Gloire, had been launched in 1859). But most ships in the mid-1800s were wooden, and ironclads had yet to be used in combat.

It was the fate of the Union blockaders at the Battle of Hampton Roads to be the guinea pigs. Their crews were shocked to discover their cannonballs bouncing off the strange ship’s sides.

Shock soon turned to horror: the Virginia rammed and sank the sloop USS Cumberland and set ablaze with red-hot cannon balls the frigate Congress, while the frigate Minnesota ran aground.

The implications were staggering. If the South could break the Union’s blockade using ironclads, the Confederacy would win the war. If the U.S. Navy’s wooden ships were helpless against ironclads, so too were the stout oaken ships of the Royal Navy, France and Russia. The clang of cannonballs ricocheting off metal armor was a declaration that most of the world’s warships were now obsolete.

Yet if that wasn’t amazing enough, what came next was. The following day, March 9, another strange ship charged into Hampton Roads like sea cavalry to the rescue. With a single turret perched on a low, flat hull, the USS Monitor was described by observers as a “cheesebox on a raft.”

Ironically, the first ironclad battle itself was inconclusive. Despite much maneuvering and firing, neither ship was really able hurt the other.

But that wasn’t the point. Sitting at our computers, wired to a world of Internet and drones and nuclear weapons, it’s easy to forget just how amazing ironclads were in an era when high tech was a slow, smoke-belching steam locomotive. Before the Monitor versus Virginia duel, naval technology had been static. The ships of the sixteenth-century Spanish Armada weren’t that different than Admiral Nelson’s ships of the line and frigates of the early 1800s. Nations like Britain and France might compete in numbers and size of ships, but not in their design.

However, after the Battle of Hampton Roads, technology became the crux of naval warfare. Consider the changes between 1862 and World War I: steel ships propelled by coal and oil instead of sail, ships with gun turrets insteads of rows of fixed guns, rapid-fire cannon, smokeless powder, radio communications, torpedoes, mines and submarines. Extend the timeline to 1962, and you have aircraft, guided missiles, radar, sonar, electronic warfare and nuclear weapons.

If technology has become key, then so are the resources that support it. Eighteenth-century Britain fought wars to ensure that it had access to naval supplies such as wood, hemp and tar. In the Industrial Age, different resources were needed. Not just iron, coal and oil, but intellectual and skilled resources: naval architects, engineers, mechanics and sailor with technical skills. Which meant that those nations with the industrial, mineral and mental resources would become dominant.

Still, someone watching the floating cheese box battle the floating butter dish can be forgiven for not appreciating what lay in the future. Just watching the first duel of two ironclads would have been enough for one lifetime.

Michael Peck is a contributing writer for the National Interest. He can be found on Twitter and Facebook.

Image: “The Monitor and Merrimac: The First Fight Between Ironclads.” Wikimedia Commons/Public domain