In science classes, we learn all about chain reactions: one thing happens, which causes another thing to happen, which causes another thing to happen, and so on.

And that's great for science.

But when it comes to historical events, they tend to be less chain reaction and more a confluence of multiple factors.

In other words, history typically doesn't happen because one thing happened, and then another, and then another. Usually it's more like there were several different, largely unrelated things going on, and they all came together and resulted in something else happening.

In 1803, the Louisiana Purchase was the something else that happened.

We could spend weeks talking about all of the things going on around the world that resulted in the Louisiana Purchase…but we won't. Instead, we'll focus on the goings-on within the borders of three of the biggest movers and shakers on the Louisiana Purchase scene: the United States, France, and…Haiti.

That's right, Haiti.

The Louisiana story is a fascinating one, so pull up a bean bag chair and get comfy—you're not going to want to walk away from this tale without getting all of the deets.

America Looks Beyond Its Starter Home

Thomas Jefferson was the president of a small, young country. In his day, the Great American West was just the land between the Appalachian Mountains and the Mississippi River.

The United States, which in 1800 was about 865,000 square miles and had a population just a hair over 5 million, was having some growing pains. The country was starting to feel like that cute little condo that was perfect until we adopted all those dogs, or like the strained peas that sustained us when we were babies but aren't enough now that we've grown some chompers.

We've got analogies all day, but the point is this: America was outgrowing its britches.

Eyes kept straying beyond the nation's western border, which at that time was the mighty Mississippi River. Beyond those banks, thought many Americans, lay the future of the United States. There were rumors of lush farmland, plenty of room for home sites, and all kinds of fun and exciting natural resources. "We gotta get to the other side of that river," Americans said to themselves.

The problem, though, was that all of that land belonged to someone else.

Native Americans? Gosh, no, their needs weren't really a huge concern to the settlers looking for cheap and fertile land.

We're talking about France. Or was it Spain? The territory was changing hands around the turn of that century. But whoever was in charge, the United States knew it wasn't them.

Even though America really wanted to know what lay beyond the Mississippi, the country's primary concerns were (a) making sure they could use that river to transport goods and people and whatnot and (b) making sure that, whoever owned the land, they weren't going to make any trouble for the United States by shutting down commerce on the river or in the port of New Orleans at the mouth of the river.

They'd had enough trouble. They'd only been an independent nation for 24 years, and they'd already since had a few dust-ups with their colonizing neighbors.

President Jefferson was a smart guy, and he knew that the chances of France (or was it Spain?) handing over the Louisiana Territory all peaceful and cheap-like were slim to none, and he didn't think the United States needed all that land anyway. But he knew that something had to be done to secure American rights to the Mississippi River and New Orleans.

He also knew that the long-term success of the teenage United States had a lot to do with its neighbors, and, as we all know, some neighbors are a lot cooler than others.

Spain, he reasoned, would be a pretty good neighbor. Their empire-building had slowed down quite a bit in recent years, and at that point, they weren't exactly the warmongering type. In fact, they'd been Louisiana's landlords for a while, and for the most part, it had been a pretty decent and mutually advantageous arrangement.

Unfortunately, Spain was no longer the rightful owner of Louisiana, thanks to a secret deal they'd made with France (which everyone found out about), ceding the territory back to Napoleon in exchange for some ownership rights in the area we now know as Tuscany.

Great Britain was another possibility, though kind of a distant one. They already had a huge swath of land to the north, a place we refer to today as Canada, and it hadn't been so long ago that they'd been the owners of what was now the United States itself.

Having Britain as a neighbor to the north and to the west was a thought that didn't settle too well with most Americans. They'd fought hard for their independence from England, and to be suddenly surrounded by them again...well, it kind of seemed like a step backwards.

So that left France.

France, the land of couture, fancy food, and expensive wine. France, the biggest empire on the planet—and arguably one of the most violent—who was going through its own crazy revolution and was currently being ruled by a guy who was fast earning a reputation as the most ruthless and determined empire-builder yet: Napoleon Bonaparte.

France as a neighbor? The thought sent chills down Jefferson's spine. He didn't think for one second that France would be content to just sit there in Louisiana like Spain had done, and like pre-revolutionary France had done before that. Nope, he was pretty sure the United States would constantly be threatened by the presence of such a hangry neighbor, and America didn't have the resources to fight them off.

Worse, if France did move in and set up shop in Louisiana, Jefferson feared it would force the United States into an alliance with Great Britain, who actually had the money, troops, and equipment to shut the French down.

But America didn't want to ally with its old ruler. Been there, done that, didn't even get a lousy T-shirt.

This Louisiana thing was turning into quite the pickle. Across the Atlantic, the French Republic was dealing with a few pickles of its own.

Cornichon—the French Word for "Pickle"

France under Napoleon was a lot like the Yankees under Joe Torre or the Lakers under Phil Jackson: pretty much unstoppable.

For a little while, anyway.

But before we get to the end of Napoleon's own version of the three-peat, let's wind our way back to the beginning.

The nation of France was unofficially formed in the 5th century, following the fall of the Roman Empire…

Okay, that's too far back. Let's fast-forward to a more relevant point in time, like, say…1778.

In 1778, France was smarting over its loss to Great Britain in the Seven Years' War, which had caused the country to lose a bunch of its colonies, its military superiority, and a little bit of pride, too. And so, in an attempt to keep the Brits from causing any more trouble, France signed an alliance treaty with the brand-new United States—the cleverly named Treaty of Alliance.

This did not go over well with Britain. Four days after the treaty was signed, Great Britain declared war on France, and all heck broke loose once again. Now France was officially involved in the American Revolutionary War (remember Lafayette?), and it wasn't long before Spain joined the fray as well.

Spoiler alert: we won.

But back to France.

The Seven Years' War and the American Revolutionary War really put a dent in France's wallet. The country was already experiencing some inner turmoil as the masses started to think maybe they'd had enough of being ruled by a rich monarch while they all worked their fingers to the bone and often went hungry. The strain on the nation's finances made the whole situation even more volatile.

In 1789, King Louis XVI convened a bunch of people to try and fix France's problems. This convention was called the Estates-General, and it totally did not go the way Louis XVI had hoped. Instead, it's largely seen as the French Revolution's kick-off party.

Some historians have spent their entire careers detailing the nuances of the French Revolution, and justifiably so. There's a lot more to this revolution than beheadings, tricolor hats, and rumors of a queen saying that peasants who couldn't afford bread should maybe eat cake instead.

But for the purposes of our discussion here today, we're going to boil this monumental period in history down to one catchall paragraph. Here it comes:

From 1789 to 1799, France had four distinct governments: the National Assembly, the Legislative Assembly, the First Republic, and the Directory. All of these had major flaws, and one of them—we're looking at you, First Republic—was incredibly bloodthirsty and kind of terrifying. Needless to say, having all of these governments and all of this civil unrest and confusion really put France through the wringer. And not only was France exhausted and in a total state of chaos, none of its allies really knew what to think, either. Friend or foe? Republic or dictatorship? Nobody knew, and it seemed to change with the weather.

The Little Corporal

Enter Napoleon Bonaparte.

In 1799, after proving his military worth and impressing the right people, Napoleon decided he'd had enough of France's hot mess of a government, and he took it over.

Yep, he just took it over.

He overthrew the Directory, called himself the Grand Poobah (actually, he called himself First Consul, which maybe does sound a wee bit less pretentious than Grand Poobah), and effectively ended the French Revolution.

But he didn't end the warring.

Instead of internal wars, though, Napoleon set his sights beyond France's borders. For the next 16 years, Napoleon led his country through a series of battles that came to be known as, surprise, surprise, the Napoleonic Wars. These wars took place all around the world, from Egypt to Austria and from Russia to the Cape of Good Hope.

Now if there's anything we know for sure about wars, it's that they're always expensive.

Always. Expensive.

And the Napoleonic Wars were no different. Since France's finances had already been, um, "stretched," and since Napoleon's heart was set on creating the biggest and baddest empire the world had ever known, money was becoming an increasingly big problem.

And then there was Louisiana, like an annoying little gnat right next to Napoleon's ear.

On the one hand, he thought Louisiana would be an awesome place to establish a French empire in the Americas. In 1800, he had sweet talked the Spanish into ceding the territory back to France with visions of empire dancing in his head. New Orleans…the Mississippi River…all those sweet little islands right there in the Caribbean—what's not to love, right?

On the other hand, though, there was the prohibitive cost of all of those wars he was undertaking. He was finding out, as Spain had before him, that it was actually more expensive to maintain the Louisiana Territory than he'd thought; the whole area was becoming kind of a drain…and kind of a drag.

But Napoleon was a determined man, and he wasn't ready to give up on Louisiana just yet. He figured that once he got Europe and the rest of the Old World sorted out, he'd turn his attention back to Louisiana and his New World interests, which included a massively lucrative sugar cane business in the Caribbean.

But then something happened that he hadn't been counting on, something that totally changed his mind about that whole French empire in the Americas thing and set the stage for the United States to become the nation we recognize today.

And that something was...Haiti.

Haiti Sets France Straight-i

Haiti is about 10,700 square miles in total, making it just a little bit smaller than Maryland. That's pretty tiny, comparatively speaking.

So why are we talking about a tiny country in the Caribbean when we're supposed to be focusing on the sale of Louisiana by the French to the United States?

Because if it wasn't for Haiti, the Louisiana Purchase might never have happened.

But Haiti wasn't called Haiti back when this all went down. It was called Saint-Domingue, and it was a colony of France.

And before it was Saint-Domingue, it was part of a Spanish-colonized island called Hispañiola, thanks to Christopher Columbus and his catchy sailing of the ocean blue back in 1492. He named it La Isla Española ("the Spanish Island"; the name was later Latinized to Hispañiola), despite the fact that the people who lived there already had a name for their home: Ayiti.

The natives weren't overly stoked about having all these Spanish people setting up camp all over the place, and as a result, those camps had a habit of burning to the ground or being otherwise destroyed while their inhabitants were out and about.

Then, French pirates started wreaking havoc on Spanish settlements (and the rest of the island) in the 1540s. Between European antics, being introduced to fun New World diseases, and being turned into a slave labor force for the new settlers, the native population of the island decreased substantially.

Like, it was dang near wiped out completely.

In 1625, a few French buccaneers and some of their buddies pretty much just took over the whole western third of the island and claimed it for France, never mind what Spain said. This led to even more violence and destruction, and it also led to Spain finally giving up and ceding the area to France in 1697.

Hispañiola was then officially divided into two colonies. The Spanish colonists retained the eastern two-thirds of the island and called it Santo Domingo; the French colonists took the western third and named it Saint-Domingue.

And then they turned Saint-Domingue into a moneymaking machine. Plantations sprouted up all over the colony. Sugar and coffee were the major industries, along with indigo; at one point, the small French territory was responsible for exporting 40 percent of the world's sugar and over 60 percent of the world's coffee.

Pretty impressive for an area smaller than Maryland.

Slaves Revolt

Inconveniently, there weren't enough indigenous people in Saint-Domingue to enslave to provide the labor required for this massive agricultural enterprise, so the French started bringing in extra forced labor reinforcements from Africa. It's estimated that somewhere in the neighborhood of 500,000 African slaves were shipped to Saint-Domingue and put to work during this French farming frenzy.

But just like elsewhere in the world, the whole slavery thing didn't really sit too well with the people actually doing the work. Sure, the French landowners were getting rich, and Saint-Domingue was by far the wealthiest colony in the Caribbean, but almost none of that wealth and prosperity found its way into the hands of the indentured. And aside from the money thing, the slaves of Saint-Domingue had other issues to deal with. Beatings and other awful corporal punishments were the norm, housing was cramped and dirty and structurally iffy, and opportunities to get an education and/or move up the agricultural corporate ladder were pretty much nonexistent.

Tensions were growing.

And then, in 1790, this big ol' pot of issues started coming to a serious boil.

The year before, France's National Assembly had passed something called the Declaration of the Rights of Man and Citizen. This doc is still in use today (though it's been modified here and there over the years) and was inspired in part by the American Declaration of Independence. It basically asserts that all men are equal, that laws should only exist to protect the nation, and that individual freedoms and property rights are paramount. The document didn't specifically address slavery, but for the indentured population of Saint-Domingue, it didn't have to.

They were inspired.

They were so inspired that they tried to rebel, their efforts headed up by a wealthy land-owning Saint-Domingue resident named Vincent Ogé. This brave dude went to the United States, got a bunch of weapons, and brought them back to the island. Once he'd armed his rebel fighters, they marched to Grand Rivière, where they were totally outnumbered and swiftly shut down by the local colonists.

Ogé and his posse were eventually captured and executed, but that didn't deter the slaves of Saint-Domingue from continuing to fight.

In August 1791, 50,000 slaves and sympathizers, armed with machetes and scythes and boatloads of anger, swept across the northern part of Saint-Domingue, setting fire to every plantation they came across and torturing and murdering the families who owned them. There were a few plantation owners who managed to escape, but the damage was done: the stage for continued violence had been set.

Louverture's Overture

The French fought back once they regrouped, and the next few years on the island were brutal and bloody.

In the midst of the chaos, a Saint-Domingue man named François-Dominique Toussaint Louverture (just "Louverture" to his friends) stepped up to the plate. He organized and trained a guerilla army and initiated a prolonged series of attacks that led to several French villages surrendering to his cause.

By 1795, Louverture was in a position where he could begin to repair the intense damage the rebellion had done to his island. Now the lieutenant governor of Saint-Domingue and self-appointed general of the rebel army, he had the authority to start implementing some reforms.

In 1801, after his fancy governor-general status was confirmed by France's new leader, Napoleon Bonaparte, Louverture convened a constitutional convention and set about writing the Constitution of Saint-Domingue. This document abolished slavery, established Catholicism as the colony's official religion, and confirmed Saint-Domingue's status as a French colony.

It wasn't perfect, but Louverture and the rebels of Saint-Domingue felt like their little piece of paradise was heading in the right direction.

Not So Fast

Then, Napoleon started getting some other ideas.

For one, he was beginning to think that the only way Saint-Domingue would return to its former moneymaking glory was if slavery was reintroduced.

For two, he was eyeballing a little piece of land in America called the Louisiana Territory, which France had regained control of thanks to a secret treaty with Spain in 1800. To him, Louisiana was the perfect place to set up a French empire in the Americas, and he was all about French empires. Anyway, Saint-Domingue was a lot closer to America than France, and Napoleon was thinking it'd be the perfect place to stash troops and guns and stuff while he put his world domination plans into effect. Lousiana would be a perfect place to supply the goods and food needed to support the island's booming sugar production business.

And so, in December 1801, he sent 43,000 troops to Saint-Domingue, led by his bro-in-law, Charles Leclerc. Their mission: make sure that Saint-Domingue didn't get any funny ideas about independence from France…and then move on to New Orleans and spread the same message there.

Boy, did that plan backfire.

David vs. Goliath—Again

Between the long journey there, the battles with Saint-Domingue's army, and yellow fever, all but a few thousand of those troops died, including Leclerc. And on January 1st, 1804, the colony of Saint-Domingue threw off its colonial coat and officially became the independent nation of Haiti.

What Napoleon thought would be a quick and decisive victory had turned into an embarrassing and painful defeat.

Furthermore, with most of his 43,000 soldiers dead and his other battalions stuck in an ice storm in the Netherlands, Napoleon realized he wasn't going to be able to set up shop in New Orleans like he'd originally planned.

The ice storm and the situation in Saint-Domingue didn't really last all that long, but they lasted long enough for Napoleon to start running out of money thanks to his other world domination adventures, therefore causing him to reconsider his takeover position on Louisiana. With Haiti lost, there was no longer any reason to hold on to Lousiana.

And so, because of a rebellious island population and disease-carrying mosquitoes, New Orleans was able to avoid falling victim to Napoleon's nefarious plans. And because of that, the United States was able to buy the Louisiana Territory from him at a very reasonable price.

Thanks, Haiti.

Not So Fast, Part II

Once news of the treaty got back to the United States, not everyone in Congress was in a ratifying mood. First of all, where in the Constitution did it say that the president could authorize the purchase of a ginormous amount of land without the consent of all the states? Nowhere, that's where, and Jefferson knew it. For a strict anti-federalist like T.J., this was a major abandonment of his Democratic-Republican Party's principles.

Should they really have to grant citizenship to a bunch of foreigners, especially those who didn't speak or look English? The New England states were so freaked out by the possible influence of all those new westerners that some of them even considered joining up with Canada and seceding from the Union (source).

Not to mention that some of the states carved out of the Louisiana Territory might cause conflict with the North. Making lots of new slave states out of the territory could swing the political balance of the Senate in a pro-slavery direction permanently. It might even lead to serious national divisions. That prediction came true big time.

It wasn't only the Northern free states that were worried; the Southern slave owners had paid close attention to that successful slave revolt in Haiti and didn't want to see their own slaves getting any ideas about revolution.

And anyway, $15 million was a huge chunk of change from the new nation's budget, no matter how sweet the deal.

The deal was ultimately ratified, of course; otherwise, why would you be reading a learning guide about it? Jefferson ignored the Constitutional questions and rammed the deal through, citing "practicable" concerns that trumped Constitutional purity (source).

Maybe he was just too excited about Mardi Gras and pain au chocolat.