up. So that every inch
of ground was rendered secure and level, of which possession was taken.

Alvarado had received similar instructions from our general, and was not
to pass over any bridge or canal before the part which intersected the
causeway was completely filled up; nor to advance beyond any house until
it was levelled to the ground.

These commands were strictly adhered to, and with the woodwork and
stones of the houses which we pulled down we filled up the openings in
the causeways. In all these operations, and indeed during the whole of
the siege, our Tlascallan friends lent us the most efficient services.
When the Mexicans found we were thus by degrees pulling down their
houses and filling up the canals, they determined to alter their plan of
operation, and commenced by cutting a wide and deep opening in that part
of the causeway lying between us and the city; they deepened the lake on
each side of this opening, and threw up entrenchments near it; strong
stakes were then driven into the water to keep off our brigantines, or
that they might run foul of them on coming to our assistance. Besides
this, great numbers of canoes full of men were constantly lurking in
places where we could not see them, with orders not to rush out upon us
before we had advanced up to the entrenchments on the causeway.

One Sunday morning large bodies of the enemy came advancing towards us
from three different points, and fell so fiercely upon us that it was
with much difficulty we could maintain our ground. I had forgotten to
mention that Alvarado had posted half of the cavalry on the causeway,
for they no longer ran so great a risk of being killed, as most of the
houses lay in ruins, and there was more space for them to manoeuvre in,
without their being exposed to the attacks of the enemy from the
house-tops or from the lake. The enemy, as I have just said, advanced
bravely from three different points, one body from the quarter where the
deep gap had been made in the causeway, the other from the direction
where the houses lay in ruins, the third from the side of Tlacupa, so
that we were almost surrounded. Our cavalry, with the Tlascallans, had
the good fortune to cut their way through the dense crowds which fell
upon our rear, while our foot bravely opposed the two other bodies,
which, after a few moments' desperate fighting began to give ground; but
this was a mere stratagem of the Mexicans to allow us to take possession
of the