The Second relation letter from Hernán Cortés to emperor Charles V is one of the five "Letters of relation" written by Hernán Cortés to Charles V, Holy Roman Emperor by his name in the Holy Roman Empire, and to his mother, the queen Joanna of Castile in which he relates his trips to Mexico and the Fall of Mexico-Tenochtitlán. This second letter was dated on 30 October 1520.