In 1882, after the entry of Andrés Avelino Cáceres to the city of Huamanga—until then occupied by Nicolás de Piérola—during the War of the Pacific, the trial of Mas, who had held the position of Prefect of Ica, was ordered, as he had committed abuses in the towns of Nazca and Palpa.

[1] After the rise to power of Miguel Iglesias, Pedro Mas was appointed Prefect of Ayacucho in 1883 and during his administration he ordered the second closure of the San Cristóbal of Huamanga University on January 31, 1885.

After the first Cacerist defeat in Lima, Pedro Mas led a division of the Iglesista Army, known as the "Pacificadora del Centro" with the purpose of putting the towns of the departments of Junín and Huancavelica under Iglesias' control.

Between November 1884 and February 1885, the "Pacificadora del Centro" found effective resistance in the indigenous peasant guerrillas from Huancayo to Huancavelica and Huanta, from Ayacucho to Acobamba to Chongos Alto.

[7] The Mas regime generated the organization of Pierolist Montoneras led by various cuzqueños, such as David Samanez Ocampo, and José Lucas Chaparro who, leaving from Urubamba Province, took the city on April 3, 1895.