In 1567 the Sicilian Tercio departed for Flanders.
In 1569 Captain Pedro Gonzalez de Mendoza promoted Águila to lieutenant of his company.

In 1568 started the so-called Eighty Years' War, also called Nederlands revolt against the Spanish Monarchy.
This war will end in 1648 with the Westphalia Treaty.

In 1574 Juan del Águila participated in the battle of Mook, which was a severe blow to the Protestant rebels.

In 1576 Juan del Águila was sent to relieve the Ghent castle.
That same year, the Tercio mutinied for lack of pay and made fortifications in Alost.
Taking advantage of the situation and the power vacuum after the death of governor general Luis de Requesens, William of Orange held a general revolt, declared all Spanish and those who collaborated with them, "rebels".
So, German and Walloon troops of Antwerp switched sides and allowed Dutch rebels to enter the city, who besieged the citadel, commanded by Sancho d'Avila.
In this situation, Juan del Aguila convinced the mutineers from Alost to help his countrymen.
Thus the troops took the city.

Following this, the unfortunate Sack of Antwerp occurred.
That same year (1577) Juan del Águila was named captain.
In 1567 the Sicilian Tercio departed for Flanders. In 1569 Captain Pedro Gonzalez de Mendoza promoted Águila to lieutenant of his company.
In 1568 started the so-called Eighty Years' War, also called Nederlands revolt against the Spanish Monarchy. This war will end in 1648 with the Westphalia Treaty.
In 1574 Juan del Águila participated in the battle of Mook, which was a severe blow to the Protestant rebels.
In 1576 Juan del Águila was sent to relieve the Ghent castle. That same year, the Tercio mutinied for lack of pay and made fortifications in Alost. Taking advantage of the situation and the power vacuum after the death of governor general Luis de Requesens, William of Orange held a general revolt, declared all Spanish and those who collaborated with them, "rebels". So, German and Walloon troops of Antwerp switched sides and allowed Dutch rebels to enter the city, who besieged the citadel, commanded by Sancho d'Avila. In this situation, Juan del Aguila convinced the mutineers from Alost to help his countrymen. Thus the troops took the city.
Following this, the unfortunate Sack of Antwerp occurred. That same year (1577) Juan del Águila was named captain.
Juan del Águila