One of the principal justifications for first seeking out and then governing the inhabitants of the New World was that of religion. Monarchs and church authorities felt the duty to spread Christianity to all peoples of the world. This determination had included, for example, the Spanish war of "reconquest," an endeavor completing a Christian struggle against Muslims dating back to the year 711, when Muslims invaded southern Europe from North Africa. The year Christopher Columbus sailed on his first voyage, in fact, was the year the Spanish Christians defeated the last remaining Muslim forces in Spain.

Similarly, in 1478 Queen Isabella and King Ferdinand instituted the Spanish Inquisition, which continued a line of previous efforts over several centuries to ensure the primacy of Christian beliefs and extinguish "heretical" practices. Methods of enforcement included secret trials, confiscation of property, and public execution. In this way, the Inquisition...