The Conquest cost the lives of several hundred thousand of the labouring class; and numbers more were taken away from the cultivation of the land to work as slaves for the conquerors in building houses and churches, and in the silver-mines.
When the inhabitants were taken away, the ground went out of cultivation, and much of it has relapsed into desert.

Even before the Conquest, Mexico had been suffering for many years from incessant wars, in which not only thousands perished on the field of battle, but the prisoners sacrificed annually were to be counted by thousands more, while famine carried off the women and children whose husbands and fathers had perished.

But the slaughter and famine of the first years of the Spanish Conquest far exceeded anything that the country had suffered before.
At the time of the Conquest of Mexico the Spaniards let the native irrigating-works fall into decay; and they took still more active measures to deprive the land of its necessary water, by their indiscriminate destruction of the forests on the hills that surround the plains.

When the trees were cut down, the undergrowth soon perished, and the soil which had served to check the descending waters in their course was soon swept away.

During the four rainy months, each heavy shower sends down a flood along the torrent-bed which flows into a river, and so into the ocean, or, as in the Mexican valley, into a salt lake, where it only serves to injure the surrounding land.