A Line on a Map, A Legacy Across a Hemisphere

MAXWELL AIR FORCE BASE, Ala. —Why does Brazil speak Portuguese while much of Latin America speaks Spanish?

It seems like a simple question, but the answer reaches back more than 500 years to a diplomatic agreement that reshaped the Western Hemisphere.

That question opened a recent Air University lecture where Matt Millard, an assistant professor of national security policy at Air University's Air Force Global College and chair of the Department of Strategy and Security Studies, explored how a dispute between Spain and Portugal became one of history's most consequential international agreements and why its effects are still visible today.

Millard challenged students to look beyond geography and consider how diplomacy, competition and political decisions can influence nations for generations.

"Have you ever wondered why Brazilians speak Portuguese but much of the rest of Latin America speaks Spanish?" Millard asked. "While to American ears Spanish is often considered ubiquitous throughout Latin America, the region is actually incredibly diverse."

To answer that question, Millard took students back to the Age of Exploration, when Portugal and Spain competed to establish new trade routes and expand their influence beyond Europe.

"The competition for who could reach Asia by water first would become the 15th century equivalent of the Space Race," he said.

Millard explained that Portugal's maritime dominance and the search for new routes to Asia transformed exploration into a contest for economic and political influence. Columbus' voyage westward only intensified that rivalry.

"King John II recognized what Columbus may or may not have known: the islands technically belonged to Portugal and not Spain," Millard said as he described the competing claims that followed Columbus' return from the New World.

The disagreement eventually led Pope Alexander VI to establish a line dividing Spanish and Portuguese claims before the two kingdoms negotiated the Treaty of Tordesillas. Moving the line farther west ultimately placed part of South America within Portugal's sphere of influence, laying the foundation for Portuguese settlement in what is now Brazil.

"The Portuguese had successfully argued that since they already had a naval presence in the vicinity of the Azores, 100 leagues was not enough area to prevent encounters between Spanish and Portuguese ships," Millard said.

That adjustment carried lasting consequences. The treaty shaped patterns of colonization, influenced political boundaries and contributed to the linguistic and cultural differences that still define much of Latin America today. As Protestant states later rejected papal authority, other European powers challenged those agreements, opening another chapter in the competition that reshaped the Americas.

The lecture reflects Air University's approach to professional military education, where historical case studies provide insight into enduring questions of strategy, diplomacy and statecraft. Across the university's integrated enterprise, students examine how national interests, military power and political decisions interact over time, developing the judgment needed to understand today's operating environment and the challenges facing the Joint Force.

Rather than treating the past as a collection of dates and events, Air University challenges students to explore why leaders made the decisions they did, what information they had available and how those choices shaped future generations. That approach connects academic scholarship with military decision-making and helps forge expert joint warfighters prepared to solve operational problems across the Joint Force.

Millard closed by reminding students that Latin America's history cannot be reduced to simple assumptions.

"While it is easy to characterize Latin America as a region where one language is spoken and is comprised of roughly equivalent societies and peoples, nothing could be further from the truth," he said.

For Air University students, that lesson extends well beyond the history of one treaty. Examining how diplomacy, strategic competition and political decision-making shaped the modern world reflects the university's approach to preparing leaders for future challenges. By connecting historical scholarship with contemporary military education across its integrated enterprise, Air University helps develop leaders prepared to think critically, make informed decisions and contribute to solving operational problems facing the Joint Force.