In the years between 1519 and 1521, the Aztec Empire was conquered by the Spanish under the leadership of Hernan Cortés. When they arrived on the coast of Mexico, Montezuma or Moctezuma I sent gifts to Cortés to welcome them. As Cortes arrived in Mexico on the birthday of the Aztec god Quetzalcoatl, Montezuma thought that the words of the Aztec mythology have come true that Quetzalcoatl would come on earth as a man. This fact proves that the Spanish conquistadors arrived during the rule of Moctezuma.
The main reason why this was the case is because Industrialization was an incredibly new phenomenon, and very few people could have predicted just how bad it was for the environment and for people's health.
