What was Hernando de Soto known for?

Hernando de Soto is primarily known for leading the first European expedition into what is now the Southeastern United States. His exploration, which took place in the 1530s, was significant in that it opened up vast areas of the territory for European influence and eventual colonization. De Soto's journey included the exploration of present-day states such as Florida, Georgia, Alabama, Mississippi, and Arkansas, and it is noted for its encounters with various Native American tribes.

His expedition was characterized by a search for gold and other resources, contributing to European knowledge and mapping of the region. The impacts of de Soto's exploration were profound, leading to the eventual establishment of Spanish claims to territories in North America, and later influencing subsequent explorers and settlers in their endeavors.

The other options do not accurately reflect de Soto’s contributions or roles in history. For example, establishing Savannah pertains to James Oglethorpe and the founding of the Georgia colony much later in the 18th century, while the title of the first Royal Governor of Georgia also falls to Oglethorpe. Additionally, the term "defeating the Spanish" does not apply to de Soto as he was a Spanish explorer who aimed to expand Spanish influence rather than defeat it.