In 1492, Christopher Columbus made landfall in present-day San Salvador in the Bahamas while trying to reach the East by sailing westward. Over the next half century, the Spaniards built a colonial empire, expanding their hold in South America and conquering vast empires. Leaders in these expansionist efforts were the conquistadors (conquerors), who led several expeditions in search of gold, wealth, and fame in various areas of the Americas. Read on to discover the stories of the most famous conquistadors and how they overthrew ancient empires.Setting the Stage: The Age of ExplorationPortrait of a Man, Said to be Christopher Columbus, by Sebastiano del Piombo, 1519. Source: Wikimedia Commons/Metropolitan Museum of Art, New York CityIn January 1492, the Italian-born seaman and explorer Christopher Columbus obtained the support of Isabella of Castile and Ferdinand of Aragon for an ambitious endeavor: reaching India and the Spice Islands by sailing westward across the Atlantic Ocean.By then, King John II of Portugal had already lent his patronage for a sea voyage under the command of Bartolomeu Dias, tasked with finding a route to the East by sailing around Africa. As a combination of circumstances, including the weakening of the Mongol Empire and the resurgence of Muslim rule on the Mediterranean shores, had hindered the lucrative spice trade, the European powers were forced to find alternative routes that would allow them to reach India and Cathay (present-day northern China) directly.The need for a quick and reliable way to the Spice Islands, along with fear of a Portuguese monopoly and a desire for adventure and conquest, undoubtedly influenced the Spanish monarchs decision to finance Columbus first voyage. However, instead of finding a new sea route to the East, the Italian-born navigator ended up making landfall on an unknown continent: the Americas.After the 1494 Treaty of Tordesillas between Portugal and Spain assigned to the latter all lands west of an imaginary line 370 leagues west of the Cape Verde Islands, the Spaniards, spurred by stories of gold and rich empires, began launching expeditions on the mainland of the new continent. Leaders of this fast-paced conquest were the conquistadors.A New WorldviewThe 1507 Waldseemller Map, the first document showing the lands discovered by Columbus as a New World named after Amerigo Vespucci. Source: Library of CongressBesides the lust for gold and spices, religion was also a key driving force behind the conquistadors expeditions against the Indigenous people of the West Indies. In 1492, the conquest of Granada, the last Muslim stronghold in the Iberian Peninsula, ended the Reconquista (a series of centuries-long campaigns against Muslim rule) and led to the resurgence of missionary fervor and crusading spirit.In 1493, following a petition from the Catholic Monarchs, Pope Alexander VI, a Spaniard, issued the bull Inter Caetera, granting Spain jurisdiction over all lands west and south of an imaginary line 100 leagues west of the Azores and Cape Verde Islands that was not already ruled by a Christian king.Remarking that in our times especially the Catholic faith and the Christian religion be exalted and be everywhere increased and spread, the pope urged the monarchs to lead the peoples dwelling in those islands and countries to embrace the Christian religion; nor at any time let dangers or hardships deter you therefrom, with the stout hope and trust in your hearts that Almighty God will further your undertakings.In the following decades, the Spanish conquistadors frequently cited religious fervor as the ideological basis for their expeditions, claiming to have gone to the newly discovered continent to serve God. To aid in the conversion efforts, Dominican and Franciscan friars often accompanied the conquistadors in their campaigns.Portrait of Bartolom de las Casas, by anonymous, 16th century. Source: Wikimedia CommonsAlarmed by the ruthlessness of conquest and its disastrous effects on the Indigenous populations, some friars became concerned by the moral aspect of colonial rule. As the Age of Exploration had redrawn the world map, the Europeans were also faced with the challenge of incorporating a new continent and its inhabitants into the existing worldview.Theologian Juan Gins de Seplveda, drawing on Aristotles claim that some people are slave by nature, justified Spains brutal conquests, declaring that the lesser humans (homunculi) inhabiting the Americas were inferior to the Spaniards as children are [to] adults, as women are [to] men, as apes are [to] human beings.Fray Bartolom de las Casas, however, denounced the violence against the Indigenous people, calling for a peaceful evangelization. Seplveda and las Casas famously clashed in a debate held in Valladolid in 1550, where las Casas criticized Spains system of exploitation in the Americas. They violently forced away Women and Children to make them Slaves, and ill-treated them, consuming and wasting their Food, which they had purchased with great sweat, toil, and yet remained dissatisfied too, accused the Dominican friar in Brief Account of the Destruction of the Indies (1552).Who Were the Conquistadors?Landing of Columbus, by John Vanderlyn, 1847. Source: Wikimedia CommonsWhile some conquistadors came from other parts of Europe or even Africa, the majority of the soldiers-turned-explorers who ventured across South America were Spanish. Many were so-called hidalgos, sons of lesser nobility who embarked on expeditions to the New World in search of wealth, fame, and upward mobility.Upon reaching the early Spanish settlements in South America, the future conquistadors were usually able to amass considerable wealth by acquiring lands or through the slave trade. As stories of empires with precious artifacts and immense reaches began to spread among the settlers, they embarked on expeditions on the mainland of South America with the hope of securing the treasures for themselves and their monarchs.Over the second half of the 16th century, the conquistadors exploits overthrew the Aztec and Inca empires, whose populations were ill-equipped to defend themselves against the firearms, horses, and wheeled vehicles employed by the European invaders. The indigenous populations also lacked immunity against the deadly diseases spread by the Europeans, such as smallpox and measles, leading to the outbreak of deadly epidemics.Hernn Corts: Conqueror of the Aztec EmpirePortrait of Hernn Corts, by anonymous, 17th century. Source: Wikimedia Commons/Naval Museum of MadridBorn in 1485 in Medelln, Castile, in an ancient lineage, Hernn Corts sailed for the Americas in 1504. After settling on the island of Hispaniola, where Christopher Columbus had made landfall twelve years earlier, Corts took part in Diego Velzquezs 1511 expedition, which led to the conquest of Cuba. He was then elected alcalde (mayor) of Santiago, the islands new capital, twice.In 1518, Velzquez appointed Corts captain-general of an expedition tasked with exploring the continents mainland, where the Spanish authority planned to establish a colony. A charismatic figure, Corts soon gathered six ships and around 300 men, and before the jealous Velzquez could claim leadership of the mission for himself, he hastily left Cuba with his fleet.In 1519, Corts and his crew landed on the southern Mexican coast, where he established Veracruz and was elected captain by his soldiers. As the conquistador and his men began exploring the Mexican interior, they came into contact with the Aztec Empire.Exploiting the political crisis of the empire to his advantage, Corts formed alliances with those who resented the tributes imposed by the Aztecs, such as the nation of Tlaxcala, then in a state of chronic war with the Aztec emperor Montezuma II. In November 1519, Corts entered the capital of the empire, Tenochtitln, where he was greeted by Montezuma. Believing the Aztec monarch planned to lay a trap for the Spaniards, Corts seized Montezuma.In 1520, however, after Pedro de Alvarado massacred several Aztec chiefs (more on that later), the Spaniards were forced to make a hasty and costly exit. The following year, Corts returned to Tenochtitln, and after a siege, conquered it on August 13, effectively ending the Aztec Empire.Francisco Pizarro: Toppling the Inca EmpirePortrait of Francisco Pizarro, by Amable-Paul Coutan, ca. 1834-1835. Source: Wikimedia Commons/Palace of VersaillesThe illegitimate son of Gonzalo Pizarro, Francisco Pizarro arrived at Hispaniola two years before Corts. After joining Vasco Nez de Balboas expedition, which led the Spaniards to catch their first glimpse of the Pacific Ocean, Pizarro became the mayor of Panama and acquired considerable wealth.In 1523, when he was 48 years old, the conquistador embarked on a series of expeditions on the west coast of South America, hoping to extend Spains reach on the continent. While the first two missions were unsuccessful, Pizarros party learned of the existence of a civilization located in present-day Peru: the Incas. As the governor of Panama called off the expedition, Pizarro refused and, along with thirteen of his men, continued to explore the coast.When the governor again refused to support his efforts, Pizarro left South America to personally ask Charles I of Spain (Holy Roman Emperor Charles V) for permission to continue his mission. The meeting with the Spanish monarch was successful, and after receiving titles and privileges, Pizarro returned to Peru, where the unresolved struggle for succession had weakened the Inca Empire.The Funerals of Inca Atahualpa, by Luis Montero, 1867. Source: Wikimedia Commons/Lima Art Museum, PeruIn April 1531, Pizarro made contact with emissaries of the Inca emperor, Atahualpa, who invited him and his men to Cajamarca, the Inca capital. After Atahualpa refused to convert to Christianity and accept the authority of Charles V, Pizarro ordered an attack. In the ensuing Battle of Cajamarca (1532), the Incas, shocked by the firearms of the Spaniards, were defeated.Following Corts example, Pizarro seized Atahualpa, requesting a ransom in gold. Though the Incas complied with Pizarros demands, the conquistador had the emperor killed, and in 1533, entered the Inca capital, Cusco. The conquistador then consolidated Spains rule in Peru until, in 1541, he was killed by a group of supporters of Diego de Almagro, his second in command, who had been executed on Pizarros order.Hernando de Soto: Exploring North AmericaDiscovery of the Mississippi by De Soto, by William Henry Powell, 1853. Source: Wikimedia CommonsAfter spending his younger years on the family estate at Jerez de los Caballeros, Hernando de Soto joined an expedition to the West Indies in 1514. Settling in Panama, he amassed considerable wealth through slave trading, and in the 1530s, he took part in Pizarros conquest of the Inca Empire.Despite playing a central role in the expedition, de Soto grew dissatisfied with Pizarros leadership, and in 1536, he was back in Spain. The following year, the Spanish crown made him governor of Cuba and entrusted him with organizing the conquest of present-day Florida, where he landed in May 1539.Over the following years, de Soto and his men, led by native guides, traveled to present-day Georgia, the Carolinas, Tennessee, and Alabama. In October 1540, however, a group of Indians attacked them near Mobile Bay. The clash ended with heavy losses for both sides, with the Spaniards also losing most of their treasure and equipment.After a month-long pause, de Soto resumed his exploration of the inland, crossing Alabama and then moving west through Mississippi while under constant attacks by the Indians stationed in the area. In May 1541, the conquistador and his soldiers crossed the Mississippi River and headed to Arkansas and Louisiana. The following year, however, de Soto died of a fever.Pedro de AlvaradoPedro de Alvarado, by Toms Povedano, 1906. Source: Wikimedia CommonsBorn in the province of Extremadura, Pedro de Alvarado was a hidalgo of a minor noble family. In 1510, he and several of his brothers sailed to the Americas, hoping to gain fame and fortune by participating in various expeditions of conquest.Then, in 1519, he accompanied Corts on the expedition that would overthrow the Aztec Empire. The following year, when Corts left Tenochtitln to meet a hostile Spanish force and left him in command of the garrison in the city, de Alvarado ordered the massacre of numerous Aztec chiefs who had gathered to celebrate the festival of Toxcatl. In response, the Aztecs besieged the Spaniards quarters.When Corts returned to Tenochtitln, he ordered a retreat from the city, aware that the situation had turned against the Spaniards. On the night of June 30, 1520, the Spanish soldiers began to quietly leave the city, but they were spotted by the Aztecs. In the ensuing clash, Alvarado managed to escape, but the Spaniards suffered many losses. The event became known as the noche triste, the sad night.In 1522, when Corts forces recaptured Tenochtitln, Alvarado became its first alcalde. Over the following years, he embarked on a series of expeditions of conquest of his own against the kingdoms located in the lands once home to the Maya Empire, using a divide-and-conquer strategy to defeat the Quich and Cakchiquel of Guatemala. He died in 1539 while trying to crush an uprising in Mexico.Diego de AlmagroDiego de Almagro (left) and Francisco Pizarro (right) in a drawing from Guaman Poma, Nueva cornica y buen gobierno (1615). Source: Det Kgl. Bibliotek (Royal Danish Library), CopenhagenDiego de Almagro arrived in the New World in 1524, where he accompanied fellow conquistador Francisco Pizarro in the expedition that ended with the fall of the Inca Empire. Despite the successful outcome of the mission, however, a bitter rivalry arose between Pizarro and de Almagro, resulting in political instability in New Castile, the Spanish colony established in the vast region previously under Inca rule.In 1534, when Diego de Almagro, acting on the order of King Charles I (Emperor Charles V), joined an expedition to present-day Chile, the Indians of Peru rose against the new Spanish rule, attacking the fortress of Cusco. Rushing back, de Almagro put an end to the insurrection and imprisoned Hernando and Alonso Pizarro, Franciscos brother, accusing them of having disobeyed his direct orders.Soon afterward, Pizarro arrived in Cusco, where he defeated de Almagro and executed him. In 1535, while Pizarro was in Lima, a group of Almagros former supporters attacked his palace on June 26, killing the conquistador.Vasco Nunz de Balboa: Discovering the PacificPortrait of Vasco Nunz de Balboa, by anonymous, 19th century. Source: Wikimedia Commons/Naval Museum of MadridBorn into a family of the minor nobility, Vasco Nunz de Balboa soughtlike many other hidalgosto make his fortune in the West Indies, where he arrived in 1500. Failing to prosper as a farmer in Hispaniola, he embarked on an expedition to aid a colony founded in present-day Colombia as a means to escape his creditors.After the colonists moved to the less hostile coast of the Isthmus of Panama and founded Santa Mara de la Antigua, Balboa was elected as one of the two town magistrates. By 1511, he had become the undisputed leader of the first stable Spanish settlement, and King Ferdinand II made him interim governor. Over the following years, Balboa launched a series of ruthless attacks against the Indian tribes of the area, combining the use of barter and brutal force to extract information.Upon hearing stories of a sea and a gold-rich empire lying to the south, Balboa planned an expedition. However, King Ferdinand II, displeased by the charges brought against the conquistador, made Pedro Arias Dvila the leader of the mission. The enmity between the two Spaniards would have disastrous consequences for Balboa.Monument of Vasco Nunz de Balboa in Panama City, photograph by Carlos Siu, 2012. Source: Wikimedia Commons/FlickrMeanwhile, Vasco Nunz de Balboa, set on carrying out his enterprise, sailed from the Isthmus of Panama in September 1513. At the end of the month, after a harrowing march across a dense jungle and swamps, he and his men finally sighted the Mar del Sur (Pacific Ocean), taking possession of the expanse of water and the nearby lands for the monarch.Pleased by Balboas success, Ferdinand II made him adelantado (governor) of the Mar del Sur, Panama, and Coiba. Meanwhile, the friction between Balboa and Dvila continued to rise, and when the latter feared Balboa would testify against him in an upcoming judicial review, he sentenced the conquistador to death. Balboa was beheaded in January 1519.