Sure, Leonardo da Vinci created some great art or whatever, and some cool inventions that make life easier. We also found out he was a weapons developer and he designed some badass military devices.
Then we took a closer look at those designs and realized Leonardo's a lot less artist and a whole lot more Darth Vader.
"And if it should happen that the engagement was at sea, I have plans for constructing many engines most suitable either for attack or defense, and ships which can resist the fire of all the heaviest cannon, and powder and smoke."
- Leonardo da Vinci
Yeah, right there is everything you need to know about how Leonardo da Vinci approached military design. That's a fucking ancient submarine holding a gigantic cartoon knife. And Leonardo is known for the freaking Mona Lisa? Look at that thing!
But what good is a submersible ship-cleaver without a SEAL team to rig charges?
That's right. Leonardo designed his own SEAL team.
Why it Would Have Worked:
The Crusades turned city-states like Venice and Genoa into superpowers thanks to the usefulness of their mighty navies. If anybody was going to stand a chance against these two powers, they needed men like Leonardo to sink their fleets swiftly and silently. Underwater warfare would have turned every drop of water in the Mediterranean into a war zone that no ship would be safe in unless they had pledged allegiance to your kingdom. Your fleet would have been as feared as Poseidon himself.
Seriously, could this possibly be any more pimp?
As for the scuba gear, it was specifically designed for "sneak attacks on enemy ships from underwater." Just the loss of a few enemy ships while in dock would have been enough for every navy on the planet to fear you.
Like this, only with more explosions.
The gear itself was incredibly complex and even included a pouch for the SEALs to piss in. The plus-side: Much like modern SEAL units, urine keeps you warm in cold waters. The downside: None. The competition: None. The possibilities: Endless. With Venice stormed by your SEAL team and Genoa scared into submission, you would be the undisputed ruler of the Mediterranean.
8A Robot Army
"Whoever wishes to foresee the future must consult the past, for human events ever resemble those of preceding times. This arises from the fact that they are produced by men who have been, and ever will be, animated by the same passions and thus they must necessarily have the same results."
- Niccolo Machiavelli, The Discourses
As Cracked has examined earlier, many "modern" technologies are actually way older than you might think. Take the robot: invented by the forever badass Hero of Alexandria, and perfected as a killing-machine by Leonardo da Vinci during humanity's rendezvous with antiquity.
A decoy worthy of Total Recall... until it's set for "murder death kill."
Pictured: "murder death kill."
Why it Would Have Worked:
Italy's armies were as shitty in the Renaissance as they were during World War II, and nobody knew this better than Niccolo Machiavelli of the Florentine militia. Throughout his classics texts The Discourses and The Prince, he cites countless examples about how a New Roman Empire was thwarted due to self-inflicted gunshot wounds to the foot. Italy's problems were twofold: one, a unified Italy still didn't exist, and two, Italy's dukes and princes outsourced too much of their military to Swiss mercenaries. Not only was this an enormous drain to so many kingdoms' economies, but many mercenaries happened to double-cross their employers for an even larger profit by skipping town. In short, Italy needed a local army built from the ground-up on reliability.
Veni, vidi, Vinci.
Leonardo's robots may have been a far cry from later Skynet models, but Jesus Christ... did he have his mind in the right place. It seems that Leonardo was able to effortlessly combine the profound workings of the human body with his prolific mechanical genius. Not only could this have been used to create some of the most intricate (and deadly) machines on the planet, but Leonardo would have known exactly what parts of the body he wanted them to attack.
The science behind the "Pull it out!" scene.
But even if Leonardo's robots were simply used as decoys (like the Mongols), practice shows that it would have been a better investment than the mercenaries Niccolo Machiavelli warned Italians not to trust. With Italy's enormous wealth and mutually-shared danger, men like Machiavelli might have found the droids they were looking for in the pages of Leonardo's notebooks.