What is the fine-grained topic of the following text: Cabeza de Vaca's eight years in North America, starting in 1528, set the stage for Coronado and Hernando de Soto to lead armies deep into America in the 1540's: Coronado from Mexico City and DeSoto from Cuba, Spain's "Ellis Island." Only return the topic.
Cabeza de Vaca's journey in North America and its influence on subsequent expeditions by Coronado and Hernando de Soto in the 1540's.