To Understand the conquest of Mexico, one must recognize the various human factors and the variety of motives that entered into the titanic struggle for mastery of the land. In the letters of Cortés to the Emperor Charles V, the whole gamut of ambitions—personal, national, grossly material and highly spiritual—are revealed. There can be no doubt that Cortés and the Spaniards with him were moved in the first place by a spirit of personal adventure and a desire to better their fortunes. As the panorama of the Aztec Empire opened itself before his eyes, the dream of expanding the Spanish domains came to Cortés as a justifying cause for his forward movement, so that escape or retreat appeared as treachery to his King. At the same time, as a product of the Spanish crusading era, he beheld himself in the rôle of a spiritual hero bringing the doctrine of Christian Redemption to heathen tribes sunk in idolatry and human sacrifice.