Sociedades en contacto refers to the interactions, exchanges, and conflicts that arise when different cultures, societies, or civilizations come into contact with one another. This concept is crucial for understanding the dynamics of cultural exchange, assimilation, and resistance, particularly during significant historical moments such as colonization or migration. In the context of Hernán Cortés's 'La segunda carta de relación', it highlights how the Spanish conquest of the Aztec Empire resulted in profound cultural, social, and political transformations for both the conquistadors and the indigenous peoples.