During the reign of Charles V, Spanish conquistadors toppled the two greatest New World empires, the Mexicas and the Incas, claimed much of Central and South America, and began shipping vast amounts of gold and silver back to Seville. As sovereign over this growing empire, Charles established a Spanish system of governance for the new colonies, extracting economic tribute and labor from the indigenous populations, and signed the "New Laws," making it illegal to enslave the indigenous peoples and banning new encomiendas. (He had previously banned slavery of the indigenous Americans only to reverse himself later.) Although he assembled the most powerful empire in Europe, the king could do little to control Spanish colonists in the New World who revolted against these restrictions. And he could do even less to find a permanent solution to the threat posed to his empire by the Protestant Reformation and Ottoman Turks.
The Hapsburg family, one of the greatest political dynasties in history, had ruled parts of Europe for more than 700 years before it reached the apex of its power in the 1500s under Charles. The empire's vast expansion during Charles's reign was largely the result of generations of strategic marriages among European nobility, several arranged by his grandparents Isabella and Ferdinand.
After the death of his father, Philip I, in 1516, Charles inherited control over the Netherlands, Luxembourg, and territories now in northern and eastern France. That same year, his grandfather King Ferdinand died, leaving the young man Naples, Sicily, Sardinia, Spanish America, and much of Spain.
Charles had been born in Flanders and spoke no Spanish when arrived in Spain to claim this inheritance. Soon after his coronation as Charles I of Spain, he left the country, preferring to travel throughout his realm as was common in the Middle Ages, rather than establish one capital.
His empire continued to grow. In 1519, his grandfather Maximilian I died, leaving Charles the Hapsburg lands in Germany and Austria. By borrowing money to bribe the archbishops and secular electors, Charles ensured that he was elected Holy Roman Emperor later that year. For the rest of his life, the king would rely on loans from German and Italian bankers to finance various projects and military campaigns.
Charles spent much of his reign living in northern and central Europe, opposing the growing forces of Martin Luther and the Protestant Reformation, and engaging in almost nonstop warfare, primarily against the Turkish Ottoman empire and the French. In many years, his wars cost more than the revenues of all of his states combined.
The Holy Roman Empire was not a Spanish empire, but Spain became its most powerful nation during Charles' reign as the king found himself increasingly at odds with other regions in his realm. Spain, on the other hand, had a strong history of Catholicism, was both anti-French and anti-Muslim, and remained an important source of revenue and soldiers for Charles. It also had a steady source of gold and silver: the New World.
In 1526, Charles married a woman he loved deeply, Isabella of Portugal, who died in 1539 while giving birth to the couple's sixth child. Charles never remarried. He also fathered two illegitimate children: Margaret of Parma, born before his marriage, and Juan of Austria, born long after his wife's death.
After decades of warfare and economic difficulties, Charles concluded that ruling an empire so vast was almost impossible for one man. Beginning in 1555, he divided his lands between his son, Philip II, and his brother, Ferdinand I. In 1557, having learned the language and grown to appreciate Spanish customs, Charles retired to a remote monastery in Spain where he died the following year.