Final answer:
The success of the Spaniards in México was due to their military tactics, weaponry, and unexpected allies. Additionally, the inadvertent introduction of smallpox played a significant role in their success.
Step-by-step explanation:
One of the factors that contributed to the success of the Spaniards when they arrived on the coast of México was their military tactics and weaponry. The Spanish soldiers were protected by steel armor, wielded steel swords, and had the advantage of attacking on horseback. On the other hand, the Mexica people and their allies fought with bows, arrows, and spears. Additionally, the Spanish found unexpected allies in the tribes that were previously forced to pay tribute to the Aztec Empire. One such group, the Totonacs, greeted the Spanish as liberators. Another significant factor in the Spanish success was the inadvertent introduction of smallpox into Tenochtitlan, which resulted in the deaths of thousands in the city.