"So," said Kemal. "If their god isn't bloodthirsty except after victory, they become peaceful and their god goes to sleep."

"Well, that would be nice," said Hunahpu, "but part of their theology was that besides needing sacrifices after victory, Camaxtli liked the blood. Camaxtli liked war. So they could put off the huge sacrifices until they won a victory, but they would still keep looking for more fights that might lead to such a victory. Besides, the Tlaxcalans had the same social-mobility system as the Mexica in their pre-Moctezuma days. The only way to rise within their society was either to make a lot of money or to prevail in battle. And making money was only possible for those who controlled trade. So there would have been constant pressure to start new wars with ever-more-remote neighbors. I think it wouldn't have taken the bronze-wielding Tlaxcalans long to reach the natural boundaries of their new seafaring empire: The Caribbean islands to the east, the mountains of Colombia to the south, and the deserts to the north. Conquests beyond those boundaries would not have been cost-effective, either because there were no large concentrated populations to exploit economically or to offer as sacrifices, or because the resistance would have been too strong as they came in contact with the Incas."

"So they turned to the empty Atlantic? Unlikely," said Kemal.

"I agree," said Hunahpu. "Left to themselves, I think they would never have turned eastward, or not for centuries. But they weren't left to themselves. The Europeans came to them."

"Then we're right back where we started," said Kemal. "The superior European civilization discovers the backward Indies and ..."

"Not so backward now," said Diko.

"Bronze blades against muskets?" scoffed Kemal.

"Muskets weren't decisive," said Hunahpu. "Everyone knows that. The Europeans simply couldn't come in large enough numbers for their superior weapons to overcome the numerical advantage of the Indies. Besides, there's something else to consider. The Europeans wouldn't have come straight to the heart of the Caribbean this time. The later discovery would almost certainly have come from the Portuguese. Several Portuguese ships landed on or sighted the coast of Brazil quite independently of Columbus as early as the late 1490s. But the land they saw was dry and barren, and it didn't lead to India the way the coast of Africa would. So their exploration, instead of having the urgency that Columbus brought to it, would have been occasional and desultory. It would have taken years before Portuguese ships would have entered the Caribbean. By then, the Tlaxcalan empire would already be well established there. Now, instead of Europeans finding the sweet-natured Taino, they would meet the fierce and hungry Tlaxcalans, who would be getting frustrated by the fact that they weren't able to expand easily beyond their current borders around the Caribbean basin. What do the Tlaxcalans see? To them, the Europeans aren't gods from the east. To them, the Europeans are new victims that Camaxtli has brought to them, showing them how to get back on the path to productive warfare. And those big European boats and muskets aren't just strange miracles. The Tlaxcalans -- or their Tarascan or Zapotecan allies -- would immediately start taking them apart. Probably they'd sacrifice enough of the sailors to persuade the ship's carpenter and the ship's smith to make a deal, and unlike the Mexica, the Tlaxcalans would keep them alive and learn from them. How long would it take them to have muskets of their own? Big-bottomed ships? And in the meantime, the Europeans are hearing nothing at all about the Tlaxcalan empire, because any ships that reach Caribbean waters are being captured and their crews never get home."

"So the Tlaxcalans aren't independently developing technology anymore," said Tagiri.

"That's right. All they needed was to be advanced enough to understand the European technology when they encountered it, and to have an attitude that would allow them to exploit it. And that's what the Interveners understood. They had to get Europeans to discover the new world before the Tlaxcalans came to power, back with the relatively incompetent, decadent Mexica."

"That does work," said Kemal thoughtfully. "It does allow for a believable scenario. The Tlaxcalans build European-style ships and make European-style muskets, and then come to the shores of Europe fully prepared for a war whose purpose is to enlarge the empire and at the same time bring sacrifices to the temples of Camaxtli. I suppose the same pattern would apply in Europe, too. Any nation that resisted them would be slaughtered, while those that allied themselves to the Tlaxcalans would only have to endure a tolerable level of human sacrifice. I don't think it would be difficult to imagine Europe fragmenting over this. I don't think the Tlaxcalans would lack for allies. Particularly if Europe had been weakened by a long and bloody crusade."

To Hunahpu, this sounded like victory. Kemal himself had completed the scenario for him.

"But it doesn't work anyway," said Kemal.

"Why not?" asked Diko.

"Smallpox," said Kemal. "Bubonic plague. The common cold. That was the great killer of the Indies. For every Indie who died of overwork in slavery or from Spanish muskets and swords, a hundred died of disease. Those plagues would still have come."

"Oh, yes," said Hunahpu. "That was one of the biggest problems, and there's no way to find evidence for what I'm about to say. But we do know the way diseases work in human populations. The Europeans carried these diseases because they were such a large population with lots of travel and trade and warfare -- lots of contact between nations -- so that as far as disease organisms were concerned, Europe was one vast caldron in which they could cook, just like China and India, which also had indigenous diseases. In a large population like that, successful diseases are the ones that evolve so they kill slowly and are not always fatal. That gives them time to spread, and leaves enough of the human population behind that it can recover and bring up a new, non-immune generation within a few years. These diseases eventually evolve into childhood epidemics, cycling around the large overall population pool, striking here and then there and then over there and finally here again. When Columbus came, there was no region of the Americas that had such a large population pool. Travel was too slow and the barriers were too great. There were a few indigenous diseases -- syphilis comes to mind -- but that one was exceptionally slow to kill in the American context. Fast-moving plagues were impossible because they would spend themselves in one locality and run out of human hosts before they could get carried to a new locality. But that changes with the Tlaxcalan empire."

"Zapotecan boats," said Diko.

"That's right. This empire is linked by ships carrying cargos and passengers all around the Caribbean basin. Now plagues can travel swiftly enough to spread and become indigenous."

"That still doesn't mean that a new plague won't be devastating," said Kemal. "It just means that smallpox would travel faster and strike the whole empire almost at the same time."

"Yes, " said Hunahpu. "Just as bubonic plague devastated Europe in the fourteenth century. But there's a difference now. The plague will reach the Tlaxcala empire from those earlier accidental Portuguese visitors, before the Europeans come in force. It sweeps through the empire with exactly as much devastation as it had in Europe. Smallpox, measles -- they have their terrible effect. But not one nation in Europe fell because of these plagues. No empire collapsed, any more than Rome collapsed because of the plagues in their time. In fact the plague has the effect of giving them more favorable population densities. With fewer mouths to feed, the Tlaxcalans can now produce a food surplus. And what if they interpret these plagues as a sign that Camaxtli wants them to go and win more captives for sacrifice? That might be the final spur to make them sail east. And now when they come, smallpox and measles and the common cold are already indigenous to the Tlaxcalans. They touch on European shores already immune to European diseases. But the Europeans have not been exposed to syphilis at all. And when syphilis first reached Europe in our history it struck viciously, killing quickly. It only gradually settled down to be the slow killer it had been among the Indies. And who knows what other diseases might have developed among the Tlaxcalans as their empire grew? This time I think the plagues would have worked the other way, against the Europeans and in favor of the Indies."