Approximately how many Aztecs were at the founding of Tenochtitlan? Even an estimate (“a couple thousand, tens of thousands”) would be helpful. If you tell me your source, I would be much obliged.
If you’re asking for the total population of the Aztec civilization at the time of Tenochtitlán’s foundation, I can’t help you. But this book states that at the height of the Aztec civilization (which was after the foundation of the city), the Aztec empire had a total population of between four and six million, and Tenochtitlán itself of about 200,000.
That is indeed what I’m looking for.
Will probably be hard to find. With a single city, you can try to make an estimate of the population based on the extent of the settlement, but if you’re asking about the total population including people outside the capital, you ca at best make guesses. This book sketches whý it is so difficult to get accurate pppulation figures for the time before the Spanish conquest.