Charles I of Spain vs Isabella I of Castile

Charles I of Spain was elected Holy Roman Emperor as Charles V, succeeding his grandfather Maximilian I. This election united the Spanish kingdoms, the Habsburg domains in Austria and the Low Countries, and the Holy Roman Empire under a single ruler, creating a vast European empire.

Charles V presided over the Diet of Worms, where Martin Luther was summoned to recant his teachings. Luther refused, and Charles V issued the Edict of Worms, declaring Luther an outlaw and banning his writings. This event deepened the religious divide in Europe and sparked the Protestant Reformation.

Charles V's imperial army defeated the French forces of King Francis I at the Battle of Pavia. Francis I was captured and taken prisoner to Spain. The victory solidified Habsburg dominance in Italy and forced France to renounce its claims to Milan and Naples in the Treaty of Madrid.

Imperial troops under Charles V sacked Rome, looting the city and capturing Pope Clement VII. The sack was a brutal event that shocked Europe and led to the temporary dominance of Charles V over the Papacy. It also marked a turning point in the Italian Wars.

Charles V abdicated his thrones, dividing his empire between his son Philip II (who received Spain, the Low Countries, and the Italian possessions) and his brother Ferdinand I (who received the Holy Roman Empire). This abdication was a major event in European politics, reshaping the balance of power.

Isabella married Ferdinand II of Aragon in Valladolid, uniting the kingdoms of Castile and Aragon. This dynastic union laid the foundation for the unified Spanish monarchy and enabled joint policies including the Reconquista and overseas exploration.

Isabella obtained papal approval to establish the Spanish Inquisition in Castile, aimed at maintaining Catholic orthodoxy among converted Jews and Muslims. The Inquisition operated under royal control, conducting trials and executions for heresy.

Isabella and Ferdinand completed the Reconquista by capturing the Nasrid kingdom of Granada. The surrender of the last Muslim state in Iberia ended 781 years of Islamic rule and unified Spain under Christian rule.

Isabella and Ferdinand issued the Alhambra Decree ordering the expulsion of all Jews from Spain who refused conversion to Catholicism. An estimated 40,000 to 200,000 Jews were forced to leave, causing demographic and economic disruption.

Isabella agreed to fund Christopher Columbus's expedition across the Atlantic, providing three ships and supplies. Columbus reached the Bahamas on October 12, initiating sustained European contact with the Americas and the Spanish colonial empire.

Isabella and Ferdinand negotiated the Treaty of Tordesillas with Portugal, dividing newly discovered lands outside Europe along a meridian 370 leagues west of the Cape Verde islands. This agreement shaped colonial claims in the Americas and Africa.