The ciTy in The conquesT’s wake • 75selling maize dough, cotton mantles, and foaming drinks,
and demanding cacao beans in payment—a scene very
similar to a city market there in 1500.
This is not to say that all was unchanged. In the latter
part of this chapter, I look at the ways that in two important
symbolic registers, the civic celebration and place-names,
the new Spanish ruling class was asserting its vision of the
city onto its spaces. And in the same way that we go about
our lives in the midst of long-term ecological changes, so
too did the residents of Mexico City. So as not to lose sight
of the ways in which the valley was undergoing slow and
irretrievable changes, I begin by surveying some of these
larger environmental and demographic shifts.
waTeRwoRks and The conquesT
The fall of Tenochtitlan was precipitated by the uprising
of longtime enemies and resentful vassal states who joined
with the Spaniards and waged a deadly war against the
island-bound Mexica; for many of the warriors, it seemed
like just another cycle in the indigenous power plays that
shifted power from one altepetl to the next, perhaps not
much different from the Triple Alliance’s defeat of Azcapo-
tzalco a century before. Few could have foreseen the apoca-
lyptic effects of the epidemic diseases that were unleashed
by previously unknown Old World pathogens and that
began their deadly creep through the unsuspecting popula-
tion even before the arrival of the conquistadores. Epidemic
diseases would reduce the New World populations in 1600
to one tenth of what they had been in 1500. 8 In addition
to carrying deadly pathogens, the Spanish unwittingly put
into motion a dramatic and devastating long-term realign-
ment of the delicate balance between the city and the lake,
the kind of longue durée change impossible to register in
the moment.
While Cortés initially wrote admiringly of the city in
his letters to Charles V, his attitude and those of his fel-
low conquistadores would change dramatically when they
attempted to capture the watery city. The surrounding lake
functioned like a great moat protecting the island city, and
the bridges spanning the breaks in the causeways, which
allowed the flow of water from one part of the system to
another, could be removed to further isolate the island
capital. When the Spaniards did battle within the city, as
during the Noche Triste on June 30, 1520, when Mexica
warriors ejected them, they found that their enemies used
the urban canals as transport routes for canoes filled with
as many as sixty armed warriors each. Slogging across
the canals slowed the conquistadores in their retreat, and
when, exhausted, they fled on foot along the causeways,
those raised roads served to organize them into a neat
firing line for the Mexica sharpshooting archers gathered
alongside in the lake in their canoes. Small wonder that
they emerged from the war with little appreciation of the
role that these causeways and dikes played in protecting
the city from the scourges of floods.
And once the conquistadores understood it, Tenochti-
tlan’s fragile interdependence with the surrounding waters
helped deliver it to its enemies. After Cortés had regrouped
and rebuilt his army, he reentered the valley and laid siege
to the city, beginning in May of 1521. Key to the strategy
were the city’s vital aqueducts supplying Tenochtitlan with
freshwater from the springs of Chapultepec. They were
cut on the thirteenth of that month. The Mexica were left
dependent upon water from springs within the city, which
were soon exhausted, and then only salty groundwater
remained to drink. And although the city’s surround-
ing lake made it quite defensible from soldiers on foot, it
proved more vulnerable once Cortés could use brigantines
to carry troops and munitions. The ships were assembled
at Tetzcoco, and in order for them to reach Tenochtitlan,
the great dike of Nezahualcoyotl needed to be breached,
which allowed the brigantines to travel from Tetzcoco to
reach the eastern shores of the city; to approach the city
from the south, they would also have needed to breach
the dike of Ahuitzotl (see figure 2.7). The effect of the
broken dikes on the delicate equilibrium of the system
was not immediately apparent. But in the years after the
Conquest, Spanish observers noticed a dramatic (and to
them, inexplicable) drop in lake levels. This was partially
the result of a long drought that gripped the valley in the
two decades after the Conquest, and it also seems that
the once carefully husbanded freshwater in the Laguna of
Mexico resumed its natural flow into the lower-lying Lake
Tetzcoco. 9 While water-suspicious Spaniards welcomed
less water around Mexico City, perceiving it to be less likely
to flood, the opposite was true. Their failure to repair the
dike of Nezahualcoyotl meant that the eastern side of the
city was vulnerable to salty backflows from Lake Tetzcoco,
as was the once-freshwater laguna; the Spanish inclination
to protect the city by bottling up the southern lake system
meant that crucial chinampa zones were imperiled. The
long-term effects of this distrust of water will be picked
up in chapter 9.