José Nicolás Baltasar Fernández de Piérola y Villena (known as "El Califa" ("The Caliph"); January 5, 1839 – June 23, 1913) was a Peruvian politician and Minister of Finance who served as the 23rd and 31st President of the Republic of Peru, from 1879 to 1881 and 1895 to 1899.

Though successful at first, he was later accused and impeached under Pardo's administration of misappropriating funds, but was honorably acquitted of dishonest practice after he managed to obtain the support of Congress.

On May 6, 1877, in an attempt to overthrow the government of Mariano Ignacio Prado the ironclad "Huáscar" was seized at Callao port by followers of de Pierola.

Led by the retired Navy Captain Germán Astete, it took part in the inconclusive Battle of Pacocha in which, at the helm of the monitor "Huáscar", they were forced to flee by two British ships, the "Amethyst" and the "Shah".

During the course of these events, Piérola took advantage of President Prado's absence and proclaimed himself "Supreme Commander in Chief" on December 21.

With part of the Army supporting his actions, he launched a successful coup d'état, with heavy fighting and casualties between both factions.

General Andrés Avelino Cáceres and Admiral Lizardo Montero Flores viewed their influence severely diminished.

The politician's second coup became very controversial for it was realized in a messianic and very violent fashion: over a thousand people were murdered in what was supposed to be Pierola's triumphal entry into Lima.

[3] It is generally accepted that his Presidency inaugurated the "Aristocratic Republic", a period in which the economic and political "elite" was the sole and undisputed ruling class of the country.

One of his most successful reforms was the issuing of the "Libra Peruana", gold currency of the same value as the British Sovereign, which gave Peru unprecedented monetary stability.

Thus, his second term was successfully completed in 1899 and, in the same year, Eduardo López de Romaña, a prominent member of the Civilista Party, was elected president.