waTeR and The sacRed ciTy • 37than in zones further east. By sealing off the laguna with
a dike and preventing it from draining naturally into the
lower Lake Tetzcoco, the Mexica would be able to create
a kind of reservoir, a relatively sweet zone of water fed by
the springs and freshwater rivers entering from the western
mountains. During the rainy season, the abundant fresh-
water would sluice eastward, and openings in the dikes
would allow it to flush out the salt into Lake Tetzcoco. And
when rain waters and runoff rushed into Lake Tetzcoco
from the northern lake zones, closing up the dikes could
prevent these undesirable salty waters from washing back
into the protected western enclave of the laguna. In the
course of the fifteenth century, a set of roughly parallel
dikes was built, running north to south, to create a barrier
between the ever-sweeter Laguna of Mexico and the salty
Lake Tetzcoco, as seen in figure 2.7. 34
The waterworks, those lived spaces of the city, were
represented in accounts of the city written in sixteenth-
and seventeenth-century histories as the outcome of the
actions of a pair of valley rulers, specifically Nezahualcoy-
otl of Tetzcoco and Ahuitzotl (r. 1486–1502) of Tenochtit-
lan. The linkage follows what we have seen in indigenous
histories like the Codex Mendoza that represent the alte-
petl of Tenochtitlan as the project of its rulers, beginning
with the naming of the city after Tenoch, the tribal chief,
and continuing with the expansive growth of the altepetl’s
tributary regions with his successors. These indigenous
histories are echoed in those authored by Spaniards, usu-
ally because their source material is derived from earlier
indigenous histories; such is the case in a work like the
Dominican friar Diego Durán’s Historia de las Indias de
Nueva España e islas de la tierra firme, finished in 1581, a res
gestae centered on the Mexica rulers, with its chronicle of
events structured by a framing account of the successive
reigns. Durán’s work is one of the key historical sources on
the waterworks, and its insistent linkage of waterworks to
ruler points to those indigenous representations of the city
that served as its sources as doing the same.
According to Durán, the great waterworks of the fif-
teenth century developed in tandem with the swift rise to
power of three new altepeme in the valley. In 1427, a valley-
wide war broke out as the Acolhuas of Tetzcoco and the
Mexica of Tenochtitlan and Tlatelolco attempted to free
themselves from the control of the Tepanec in Azcapot-
zalco, under the ruler Maxtla. In the wake of Maxtla’s
defeat in 1428, the political structure in the valley was
realigned, this eclipse of Azcapotzalco as the major power
in the valley leading to the rise of Mexica and Tetzcocan
fortunes. A new alliance was created by the Acolhuas in
Tetzcoco, the Mexica in Tenochtitlan, and the dissident
Tepanec of Tlacopan, the Triple Alliance, a triumvirate
that would adhere even beyond the arrival of the Spaniards
into the valley in 1519. Each of these polities was supported
by an ever-growing network of tributary states, captured
during the relentless military campaigns that the Triple
Alliance launched in and around the valley, to create an
empire that eventually reached as far south as Guatemala
(see figure 1.15). While these conquered tributary city-states
continued to act with no small degree of local autonomy,
they were obliged to pay tribute to the Triple Alliance as
often as five times a year.
As Durán tells it, the creation of the Laguna of Mexico
by the building of retaining causeways began in tandem
with the creation of the Triple Alliance and its military
victories. The first project was launched under the Mexica
ruler Itzcoatl (r. 1427–1440), under whose rulership the
Mexica state expanded dramatically; the Codex Mendoza
lists him as making twenty-four conquests. In the wake of
the military defeat of neighboring Xochimilco, he com-
manded that this conquered altepetl build a great causeway
(which functioned as both roadway and dike) from their
city northward to Tenochtitlan. This so-called causeway
of Ixtapalapa began at the causeway of Mexicaltzinco and
reached the city of Tenochtitlan. It thereby provided direct
access between Tenochtitlan and the southern agricultural
regions, which were gradually being brought into the
Mexica tributary orbit, completed with the conquest of
Chalco in 1465. 35 This causeway had the secondary effect
of protecting the southern laguna from salty inflow from
Lake Tetzcoco, but it did not seal off the system completely.
This nascent system would be further developed shortly
after 1432, when Nezahualcoyotl took the throne of
Tetzcoco and a fight broke out between him and Itzcoatl.
The Tetzcocan historian Fernando de Alva Ixtlilxochitl
presents the Tetzcocan side of the story, and tells us that the
fight was occasioned over Itzcoatl’s unjustified use of the
honorary title “chichimeca teuctli,” one until then claimed
by Tetzcocan leaders. This small irritant served as a catalyst
within a larger political contest between Tenochtitlan and
Tetzcoco as they battled for preeminence in the valley. To
attack Tenochtitlan, writes Ixtlilxochitl, “Nezahualcoyotl
mustered his soldiers for the purpose, creating an army
of some 50,000 men and they advanced to Tenochtitlan
which they entered via Tepeyacac, today the shrine of the