Spice and the Devil's Cave
Spice and the Devil's Cave is a book by Agnes Hewes that was published in 1930. This piece of historical fiction is a retroactive winner of the Newbery Honor award.
The setting is Lisbon, Portugal in the late 1490s, as Vasco de Gama, Bartholomew Diaz, and Ferdinand Magellan discuss their plans to find the elusive sea route around the Cape of Good Hope, which would enable Portugal to access the spice-rich countries of the Far East.