Spanish "conquistador" Pedro de Alvarado passed through Soconusco with a sizeable force in 1523, en route to conquer Guatemala. Alvarado's army included hardened veterans of the conquest of the Aztecs, and included cavalry and artillery; there were also a great many indigenous allies from Cholula, Tenochtitlan, Tezcoco, Tlaxcala, and Xochimilco. Alvarado was received in peace in Soconusco, and the inhabitants swore allegiance to the Spanish Crown. They reported that neighbouring groups in Guatemala were attacking them because of their friendly outlook towards the Spanish. Alvarado's letter to Hernán Cortés describing his passage through Soconusco is lost, and knowledge of events there come from the account of Bernal Díaz del Castillo, who was not present, but related the report of Gonzalo de Alvarado. By 1524, Soconusco had been completely pacified by Alvarado and his forces. Over the next fifty years, native population levels collapsed catastrophically as a result of exposure to Old World diseases, with an estimated 90–95% drop. In spite of this, the colonial administration demanded twice as much tribute in cacao as had been paid to the Aztecs prior to the Spanish invasion, and cacao continued to be an important crop throughout the colonial period. Due to the economic importance of cacao to the new colony, the Spanish were reluctant to move the indigenous inhabitants far from their established cacao orchards. As a result, the inhabitants of Soconusco were less likely to be rounded up into new "reducción" settlements, where the planting of a new cacao crop would have required five years to mature.