His name Chimalpopoca meant Smoking Shield (Chimal(li)-shield, popoca-smoke/smoking), and he came to succeed his father, Huitzilihuitl, in the year of 1418 or Four Rabbit-Nahui Tochtli.

Some sources claim different dates, varying from 1414 to 1424, but most agree on 1417-18.

In the Codex Mendoza, Chimalpopoca is depicted in a typical way of Tenochtitlan’s rulers: sitting on a reed mat, petatl, wearing a headband, xiuhuitzolli, and carrying his role of a tlatoani-revered speaker with a speech scroll coming out of his mouth. The depiction of his name is added in the form of a Mexica shield with blue rim and seven feather down balls, with curls of smoke surrounding it.

Being the son of the Second Mexica Tlatoani and his Tepanec Chief Wife, the daughter of the mighty Tepanec Emperor Tezozomoc, who by this time ruled all the lands around Texcoco Lake and the Mexican Valley, Chimalpopoca enjoyed Azcapotzalco’s continues favor, and so did Tenochtitlan alongside with him. The tribute remained greatly reduced, and the revenues from the newly acquired Acolhua provinces, including Texcoco itself, which the Mexicas received probably as a prize for their active participation in the Acolhua-Tepanec War, added greatly to Tenochtitlan’s well being.

The city continued to prosper, the buildings being further rebuilt or extended. The markets filled with luxuries along with plenty of other necessities, offering cotton clothes and precious stones, something even in Huitzilihuitl’s times was not readily available.

The first construction to carry fresh water to Tenochtitlan was finally commenced, not an overly impressive structure made out of clay and limestone, breaking down too often for anyone’s liking. Still it was better than no aqueduct at all. The water on the eastern shore of the island was brackish, good for washing but not consuming. Only the western side of the island offered readily available fresh water, and it was not as sweet tasting as the water of the mainland. Tenochtitlan people grew picky about what they were expected to consumed.

Chimalpopoca’s reign was relatively short, lasting only ten years, his military activities mainly inherited – Tenochtitlan’s participation in the Tepanec-Acolhua War, as much as the long-years’ hostilities against altepetl of Chalco, located to the south of Lake Texcoco, on the shores of Lake Chalco. Codex Mendoza lists Chalco among Chimalpopoca’s conquests, but so it does when dealing with the military efforts of his father, Huitzilihuitl, or his uncle-successor Itzcoatl. Which might indicate the long-standing hostility and raids, rather than an ultimate conquest.

Chimalpopoca died in 1427 or Thirteen Reed-Matlactli Ei Acatl and his death was not as natural as this of his predecessors. The glyph attached to his year of death in the Codex Mendoza depicts him still sitting on a mat, wearing the royal headband; yet there is no speech scroll coming out of his mouth, and his pose is slopping, eyes closed. Some sources argue about his time of death being as early as 1424 or as late as 1432.

The upheavals in Azcapotzalco’s royal house sent huge waves of unrest throughout the entire Tepanec empire, hitting Tenochtitlan’s shores with a great strength. Tezozomoc, the man who had ruled the Mexican Valley with a stony fist for quite a few decades died in 1426, leaving two dominant heirs among multitude of eligible sons.

Tayauh, or Tayatzin as most of the records tend to add the honorific ‘tzin’ to this man’s name, was the son the dying emperor named for a successor, but his brother Maxtla thought he would do better occupying Azcapotzalco’s throne.

Chimalpopoca, still a young man of barely twenty, acted unwisely by supporting the legitimate heir vocally, openly, with great zeal. It is said that both his half-uncle Itzcoatl, his Head Adviser at this time, and his half-brother Tlacaelel, the Chief Warlord, advocated Tenochtitlan’s neutrality in this matter, advising to leave the Tepanec heirs sort their differences between themselves. However young and probably impressionable Chimalpopoca did not heed his wise supporters’ advice. Tayatzin was a lawful new Tepanec Ruler and that was that. Tenochtitlan would side with this good man, would benefit from its continued support in the long run.

A good strategy, maybe, but for the discontent Maxtla resorting to less lawful means. Only a few moons into his reign, Tayatzin died, by poison applied by his brother Maxtla, or so many have assumed. Tenochtitlan found itself facing hostile Tepanec Capital led by the man Chimalpopoca was heard declaring openly against on more than a few occasions. Not the best of situations, as the Mexica Island was still no match for the powerful Azcapotzalco, rich with tribute and teeming with warriors forces.

What’s more, having discovered the delightful ease with which one could get rid oneself of his rivals with no intricate politics involved, Maxtla didn’t even try to make it look legal. Next to die was the ruler of Tlatelolco, Tenochtitlan’s sister-city located on a neighboring island. Then Nezahualcoyotl, the exiled Acolhua heir whom Tezozomoc allowed to live in Tenochtitlan and even in the former Acolhua Capital through the recent years, was forced to flee back to the Highlands, after a failed attempt on his life.

Chimalpopoca found himself isolated, threatened openly. And so did Tenochtitlan, unpopular now in the new royal house of Azcapotzalco.

Itzcoatl and Tlacaelel began preparing for war. Tlacaelel, the Chief Warlord was reported to be “… seen everywhere around the city, fortifying it against the possibility of a siege, strengthening people’s spirits as well…”. The island’s location was offering an advantage for a change. All the Mexica Capital needed to do was to block the causeway leading to the mainland, and make sure enough war canoes patrolled Tenochtitlan’s waters.

And then, Chimalpopoca died. Various sources disagree on the matter. Some said Maxtla has had him killed by sending assassins into Tenochtitlan’s palace. Some said he had lured the young ruler to Azcapotzalco under the pretext of an imperial feast, then took him prisoner and executed. Given the political climate of these times, the first version makes more sense.

Additional hunches pointing the accusing finger at Iztcoatl, of all people, Chimalpopoca’s Head Adviser and the man who was destined to become the next Tlatoani; the man who had the necessarily amount of royal blood, even if inherited from his distinguished father only, and no lack of other great qualifications, a hardened warrior and politician who had seen more than forty decades of life. At such time, facing the most serious crisis, about to engage in the largest military confrontation since its creation, Tenochtitlan could certainly do better with a tough leader of great clout, experience and determination. So there are scholars who suspect Itzcoatl at having his own nephew killed, the only person with a clear motive.