Spanish conquistadors had overthrown the Aztec Empire in Mexico between 1519 and 1521, and were in the process of overwhelming the Inca Empire in South America by the early 1540s.

The wealth flowing from the Americas to Spain — gold, silver, agricultural products — was transforming European economics and igniting intense competition among the other major European powers.

François I, Marguerite’s king, was acutely aware of this competition.

The Treaty of Tordesillas (1494) had divided the non-European world between Spain and Portugal along a line of longitude, but France had never accepted the validity of this division.

The French crown authorized exploratory and colonial expeditions into territory that Spain and Portugal claimed as theirs, on the principle — sometimes stated as “show me the clause in Adam’s will that excludes France from a share of the world” — that France was not bound by papal decisions made without French consent.