Romans may not be familiar with a Jaguar but they were familiar with Lions and Cheetah's and Leopards. Lions used to be native to Europe and Cheetah's were encountered in North Africa and Leopards used to be native to Spain.

I think the Romans would have cleared a area X number of feet from the perimiter of their camp and used the wood to build their camp with. Also the rainforest canopy does a pretty good job of keeping the underbrush much dryer than expected.

As for cavalry, ever seen what a horse kick can do to a Lions skull? And I doubt if any big cats would get that close to cavalry charging at them with men on their backs.

The Romans had the Gladius, the Aztecs the macuahuitl (A club with obsidian laid in one side like a swords edge)

The Romans had Pilums the Aztecs had barbed and hardened darts which were more akin to arrows.

The Romans had archers. The Aztecs did not have archers but they did have auxilary troops from Allies who used archery.

BUT it does not look like the Aztecs made much use of armor besides wood and light cotton. The Jaguar Knights IIRC fought naked draped with a Jaguar skin carrying a Maquahuitl and a small round shield.

Compare this:

http://history.missouristate.edu/jch...eapons%201.jpg
http://history.missouristate.edu/jch...eapons%201.jpg

And this:
http://history.missouristate.edu/jch...eapons%202.jpg
http://history.missouristate.edu/jch...eapons%202.jpg

To this:
http://www.globaleffects.com/C_pages...dier972_hi.jpg
http://www.globaleffects.com/C_pages...dier972_hi.jpg

The Aztecs have very good and advanced weaponry for their time and was one reason why they were the rulers.

But we are talking a fully equipped Roman Legion, which IIRC contains 10,000 men and is pretty much self sustaining and s per Roman practice erected a pallisade around their camp everynight and dug defensive ditches and earthworks and placed guards.

A Aztec with cloth armor, a obsidian sword, and a small wooden or wicker shield IMHO would not fare well in a battle with a Roman Centurion wearing Lorica Segmewntata, a Pilum, Gladius, and carrying a Scutum.

Also not all of Mexico is heavy jungle. It is towards the south but where Tenochtitlan, aka Mexico City, was the climate was more temperate.

The idea that Rome only fought primitive barbarians is complete crap to begin with (not singling you out here, but dispelling a myth). In terms of civilized enemies, Rome had to fight the Gauls, Greeks, Carthaginians, Macedonians, Seleucids, Parthians, Egyptians, etc, not to mention themselves.

If one were to place a Roman legion and a similarly-sized Aztec or Mayan army opposite on an flat piece of earth, I would firmly put my faith in the Romans being victorious. The advantages of plate, scale or chainmail armour for the Romans (depending on which era of legions, as they did evolve), being a key and deciding factor.

In light of previous and present "Rome vs Somebody" threads, I've been thinking how the professional standing legions of Early-to-Late would fare against the feudal armies of Medieval England, France, Holy Roman Empire and others around the 8th-11th Centuries. Longbows and heavily armoured knights come to mind as advantages, but they were few in number compared to peasant-based infantry.

Even if the big cats wouldn't do as much damage as I first thought, something definitely would; mosquitoes, I don't think the Roman Army would have much protection against Malaria and if they traveled by boat, well... piranhas and anacondas would be interesting for them to try and deal with. I stand by my previous statement on the forest being unable to reduce to ash like they did European forests, they may reduce the underbrush, but any large trees that would fall and not be consumed by fire would be major obstacles.

If I recall, the pilum was for what it's worth, a javelin, and they would carry at most 3 or 4 of them on their back. Now they are all well and good, but not in a wooded area. A poisoned blow dart would be more likely to make a hit than that.

Iron.

Malaria is an Eurasian disease, that the Romans must have been familiar with (in fact it plagued Italy till the Modern Era). If anything, the Romans, like the Spaniards, had the advantage in diseases.

Concerning the jungle: if "primitive" Indian tribes with low-tech equipment could clear them (hack and slash agriculture in English?), why not the Romans?

Malaria, without a vaccine, is fatal if I recall regardless of whether it is common where you are or not, mosquitoes simply spread the disease at a much faster rate.

The natives cleared the forest slowly by chopping it down, the roman army attempting to accomplish the same would be prey to guerrilla (military tactics) ambush situations until they had cleared a battlefield big enough to wage war on, and then they'd still have to get the natives to it somehow.

Relying on local wildlife to severely weaken an average Roman army is useless. They should need some time to addpat to certain creatures sure, but to think you'd loose 500 men (which is still a small amount of soldiers compared to an average Roman army) to panthers, anacondas and tarantulas is ridiculous.

Poisoned darts on the other hand could prove challenging, but they require time to aim (you'd have to hit an unprotected spot for a dart to penetrate) and in a giant battle that time could become a very big downside.

The Central/South American lack of native horses would have been a disadvantage to Mayans, Aztecs and Incas facing a Roman legionary army. Roman cavalry or allied auxiliary cavalry forces would have had little opposition in charging or running down Mesoamerican forces as they would have had little in the way of pikemen or spearmen train specifically or with experience fighting cavalry. In terms of infantry, the battle would be close-fought, being that both sides used shorter weapons (Gladius and clubs) than say, the Gauls, who used long, slashing swords. The Romans excelled in these sorts of situations.

Malaria isn't 100% fatal, its just damn annoying. Romans were trained to be the toughest sons of bitches around, they knew how to deal with mosquitoes, and if they traveled by boat, they'd beach the boat instead of just hopping off of it. The Romans were not masters of naval warfare, they were possibly the most superstitious and fearful ancient civilizations when it came to the sea, so they'd spend as little time as possible on boats.

The domestication of Eurasian animals is the deciding factor. I recommend you read "Guns, Germs, and Steel" by Jared Diamond, where he looks at why some societies advanced, conquered, and succeeded, and why others didn't.

The sections concerning why Montezuma didn't invade Spain, and why the opposite happened, focus on animal husbandry and animal diseases. The military engagements in the Spanish conquest of America were in fact a small part in the conquest - most of the work was done by disease.

And all the diseases were Eurasian ones that occur from close contact between humans and animals, which only really occurred in Eurasia, as the rest of the world has not had the same concentration of domesticatable animals. North and South America have no native horses, cows, pigs, chickens etc, the only domesticatable animals being the llama and the turkey. So diseases like smallpox (originally from cows) are completely alien to Mesoamericans. All you'd need was enough smallpox carrying soldiers, and hundreds of thousands of people could die. Much more efficient than in a battle.

But if we take that out of the equation, then the Aztecs/Maya will win the war on home ground, but I would expect them to lose the first bunch of battles. There were victories against the Spanish, and with a much more even playing field, I think the Aztecs/Maya would have been able to adapt and win. I believe that while the lack of armour would have damaged their line, they had a flexible fighting style that would have drawn the Romans away, or left them behind.

Yes, but wouldn't the Romans ally with pissed-off locals to have a more flexible army, like they did everywhere else?