Key facts and dates

The conquest of the Aztec Empire by Hernán Cortés between 1519 and 1521 marked a pivotal moment in history, leading to the collapse of a major indigenous civilisation and the establishment of Spanish control in Mesoamerica. The following timeline captures the critical events of this dramatic and violent encounter.

Timeline of key events

• 1519 (February) – Cortés departs Cuba without authorisation, beginning his expedition.
• 1519 (April) – Founds Veracruz, rejecting Cuban authority and pledging loyalty to the Spanish Crown.
• 1519 (October) – Massacre at Cholula demonstrates Spanish ruthlessness against potential threats.
• 1519 (November) – Cortés enters Tenochtitlan and is received by Moctezuma II.
• 1520 (May) – Toxcatl Massacre by Pedro de Alvarado sparks Aztec revolt.
• 1520 (30 June-1 July) – La Noche Triste sees Spanish forces driven from Tenochtitlan with heavy losses.
• 1520 (June) – Death of Moctezuma II under unclear circumstances.
• 1521 (May-August) – Siege of Tenochtitlan culminates in the city's fall on 13 August.

Hernán Cortés's unauthorised expedition and initial moves in Mexico

In 1519, Hernán Cortés, a Spanish conquistador, embarked on a daring expedition that would ultimately lead to the downfall of the Aztec Empire. His journey began with a bold rejection of authority and strategic moves to establish his presence in Mesoamerica, setting the stage for conquest.

Breaking away from Cuban authority

• Departure from Cuba (February 1519) - Cortés left Cuba without permission from Governor Diego Velázquez, who had initially supported the expedition but grew suspicious of Cortés's ambitions. This unauthorised move marked the start of his independent campaign.
• Founding of Veracruz (April 1519) - Upon arriving on the Mexican coast, Cortés established the settlement of Veracruz. He declared direct allegiance to the Spanish Crown under King Charles V, bypassing Velázquez's authority and positioning himself as a loyal servant of Spain.
• Scuttling of ships - To prevent retreat and ensure his men's commitment, Cortés ordered his ships to be scuttled and dismantled. This drastic step symbolised his determination to conquer or perish in the attempt.

Strategic alliances with indigenous groups against the Aztecs

Cortés quickly recognised that defeating the powerful Aztec Empire required more than just Spanish forces. By forging alliances with indigenous groups who opposed Aztec rule, he significantly bolstered his military strength and gained critical local knowledge.

Building a coalition of allies

• Alliance with Tlaxcala - After initial skirmishes, Cortés secured an alliance with the Tlaxcalans, traditional enemies of the Aztecs. This partnership was crucial, as the Tlaxcalans provided thousands of warriors and logistical support.
• Accumulation of other indigenous allies - Many other indigenous groups, resentful of the Aztecs' heavy tribute demands and harsh rule, joined Cortés. These alliances gave him a substantial numerical advantage and insight into Aztec strategies and terrain.
• Role of interpreters - A key figure in these alliances was Malintzin (also known as La Malinche), an indigenous woman who served as Cortés's interpreter and advisor. Her linguistic and cultural knowledge facilitated negotiations and strengthened ties with local peoples.

Key events and massacres leading to conflict in Tenochtitlan

Cortés's journey to the Aztec capital, Tenochtitlan, was marked by acts of violence and complex interactions with the Aztec ruler, Moctezuma II. These events escalated tensions and ultimately led to open conflict between the Spanish and the Aztecs.

Early encounters and violence

• Massacre at Cholula (October 1519) - En route to Tenochtitlan, Cortés learned of a potential ambush in the city of Cholula, a key Aztec ally. In response, he ordered a pre-emptive strike, killing thousands of unarmed Cholulans. This brutal act sent a clear message of Spanish ruthlessness to other indigenous groups.
• Reception by Moctezuma II (November 1519) - Upon reaching Tenochtitlan, Cortés was initially welcomed by Moctezuma II, the Aztec emperor. Moctezuma's behaviour was shaped by multiple factors: fear of the Spanish, a possible belief in the prophecy of Quetzalcoatl (a returning god associated with white skin and beards), a desire to understand Spanish intentions, and a miscalculation of their threat.
• Capture of Moctezuma - Shortly after arriving, Cortés took Moctezuma hostage, using him as a puppet to control the Aztec population. This audacious move gave the Spanish temporary leverage but deeply angered the Aztecs.

Escalation of conflict

• Toxcatl Massacre (May 1520) - While Cortés was briefly absent dealing with a Spanish force sent to arrest him, his deputy, Pedro de Alvarado, ordered an attack on Aztec nobles during a religious ceremony during the festival of Toxcatl. Hundreds were killed, triggering a widespread revolt against the Spanish presence in Tenochtitlan.
• La Noche Triste (30 June-1 July 1520) - Facing intense resistance, the Spanish attempted to flee Tenochtitlan under cover of night. Known as "The Sad Night", this retreat was disastrous, with heavy Spanish and allied casualties as the Aztecs pursued them across the city's causeways. Much of their looted treasure was lost in Lake Texcoco.
• Death of Moctezuma II (June 1520) - During this tumultuous period, Moctezuma died under unclear circumstances. Some accounts suggest he was killed by the Spanish, while others claim he was stoned by his own people for perceived weakness. His death marked the end of any hope for peaceful control.

The siege and fall of Tenochtitlan

After being expelled from Tenochtitlan, Cortés regrouped with his indigenous allies and planned a decisive assault to capture the Aztec capital. The siege of Tenochtitlan was a brutal and protracted campaign that ultimately led to the empire's collapse.

Strategies in the siege (May-August 1521)

• Use of brigantines - Cortés had small ships, known as brigantines, constructed and launched on Lake Texcoco surrounding Tenochtitlan. These vessels allowed the Spanish to control the lake, disrupt Aztec supply lines, and support land attacks.
• Cutting causeways and aqueducts - The Spanish and their allies severed the causeways connecting Tenochtitlan to the mainland, isolating the city. They also destroyed aqueducts, cutting off fresh water supplies and exacerbating conditions inside.
• Starvation tactics - With supplies blocked, hunger weakened the Aztec defenders and civilian population over the three-month siege, reducing their ability to resist.
• House-by-house fighting - The final assault involved intense urban combat, with Spanish forces and indigenous allies advancing street by street, often demolishing structures as they went. This slow, destructive process culminated in the city's fall on 13 August 1521.

Leadership changes and final defeat

• Rise of Cuitláhuac and Cuauhtémoc - After Moctezuma's death, Cuitláhuac briefly led the Aztecs but succumbed to disease. Cuauhtémoc, the last Aztec ruler, took command during the siege, fiercely resisting until his capture on 13 August 1521.
• Execution of Cuauhtémoc - After the fall of Tenochtitlan, Cuauhtémoc was initially kept alive but was later executed by Cortés in 1525 under suspicion of plotting rebellion, marking the symbolic end of Aztec resistance.
• Destruction of Tenochtitlan - The city was razed to the ground during and after the siege, with Spanish colonial structures eventually built atop the ruins, signifying the erasure of the Aztec capital.

The role of disease and Cortés's political strategies

Beyond military tactics, other factors played a significant role in the Aztec defeat. Disease devastated the indigenous population, while Cortés's political manoeuvring ensured his actions were justified to the Spanish Crown.

Impact of the smallpox epidemic

• Spread of smallpox (1520-1521) - Introduced by European contact, smallpox ravaged Tenochtitlan during the conflict, killing an estimated 40% of the population. This epidemic severely weakened Aztec resistance, as it struck civilians and warriors alike.
• Death of Cuitláhuac - The short-lived Aztec ruler Cuitláhuac was among the victims of smallpox, dying in late 1520. This loss of leadership further destabilised the Aztec defence during a critical period.
• Demographic catastrophe - The disease not only reduced the fighting force but also shattered morale, as the Aztecs had no immunity to such European illnesses, making it a decisive factor in their defeat.

Cortés's political manoeuvring

• Letters to Charles V - Throughout the campaign, Cortés wrote detailed letters to King Charles V, justifying his unauthorised actions and portraying himself as a loyal servant expanding the Spanish Empire and spreading Christianity. These writings helped secure royal support after the fact.
• Governance of New Spain - Following the conquest, Cortés was appointed governor of the newly established colony of New Spain. Despite later political challenges and conflicts with Spanish authorities, his role laid the foundation for colonial rule in Mexico.
• Legacy of conquest - Cortés's success, though marked by immense violence and destruction, opened the door for further Spanish expansion in the Americas, reshaping the region's history under colonial dominance.