Even though Carrera is often portrayed as a "guerrilla" leader, an analysis of his military campaigns between 1837 and 1840 shows that he utilized a method of fighting that can be more accurately described as hybrid warfare, a combination of guerrilla tactics and logistics with conventional combat operations. While his soldiers were not well equipped, their training in the local militias, going back to colonial times and the civil war that followed independence from Spain, enabled them to successfully fight conventional battles against the numerically superior forces of the Guatemalan and Federal governments. In 1838 the liberal forces of Morazán and José Francisco Barrundia invaded Guatemala and reached San Sur, where they executed Pascual García, Carrera's father-in-law. They impaled his head on a pike as a warning to all followers of the Guatemalan caudillo. On learning this, Carrera and his wife Petrona – who had come to confront Morazán as soon as they learned of the invasion and were in Mataquescuintla – swore they would never forgive Morazán even in his grave; they felt it impossible to respect anyone who would not avenge family members. After sending several envoys, whom Carrera would not receive – especially Barrundia whom Carrera did not want to murder in cold blood – Morazán began a scorched earth offensive, destroying villages in his path and stripping them of their few assets. The Carrera forces had to hide in the mountains . Believing that Carrera was totally defeated, Morazán and Barrundia marched on to Guatemala City, where they were welcomed as saviors by the state governor Pedro Valenzuela and members of the conservative Aycinena Clan, who proposed to sponsor one of the liberal battalions, while Valenzuela and Barrundia gave Morazán all the Guatemalan resources needed to solve any financial problem he had. The criollos of both parties celebrated until dawn that they finally had a criollo caudillo like Morazán, who was able to crush the peasant rebellion.