Leo XIII is particularly remembered for his belief that pastoral activity in political sociology was also a vital mission of the church as a vehicle of social justice and maintaining the rights and dignities of the human person.

Born in Carpineto Romano, near Rome, he was the sixth of the seven children of Count Dominico Ludovico Pecci (2 June 1767 – 8 March 1833), Patrician of Siena, Colonel of the French Army under Napoleon, and his wife Anna Francesca Prosperi-Buzzi (1773 – 9 August 1824).

On 14 February 1837, Pope Gregory XVI appointed the 27-year-old Pecci as personal prelate even before he was ordained a priest on 31 December 1837 by the Cardinal Vicar Carlo Odescalchi.

[10] The main problems facing Pecci were a decaying local economy, insecurity from widespread bandits, and pervasive Mafia or Camorra structures, which were often allied with aristocratic families.

[14] Pecci developed excellent relations with the royal family and used the location to visit neighboring Germany, where he was particularly interested in the architectural completion of the Cologne Cathedral.

Pecci encouraged the struggle for Catholic schools, but he was able to win the good will of the Court not only of the pious Queen Louise but also of King Leopold I, who was strongly liberal in his views.

In 1847, after Pope Pius IX granted unlimited freedom for the press in the Papal States,[17] Pecci, who had been highly popular in the first years of his episcopate, became the object of attacks in the media and at his residence.

It is not true that Pius IX deliberately sent him to Perugia as a way of exiling him from Rome simply because Pecci's views were perceived to be liberalistic and conciliatory, as opposed to the conservatism of the papal court.

[23] Allegedly, Pecci had been a cardinal reserved "in pectore" by Gregory XVI in the consistory of 19 January 1846, with the pope's death just over four months later invalidating the appointment since his name was never actually revealed publicly.

When Italian authorities expropriated convents and monasteries of Catholic orders, turning them into administration or military buildings, Pecci protested but acted moderately.

[7] Pope Pius IX died on 7 February 1878,[27] and during his closing years the liberal press had often insinuated that the Kingdom of Italy should take a hand in the conclave and occupy the Vatican.

[citation needed] However, the Russo-Turkish War (1877–1878) and the sudden death of King Victor Emmanuel II (9 January 1878) distracted the government's attention.

In the conclave, the cardinals faced varied questions and discussed issues like church–state relations in Europe, specifically Italy; divisions in the church and the status of the First Vatican Council.

When he firmly reasserted the scholastic doctrine that science and religion coexist, he required the study of Thomas Aquinas[30] and opened the Vatican Secret Archives to qualified researchers, among whom was the noted historian of the Papacy Ludwig von Pastor.

He also refounded the Vatican Observatory "so that everyone might see clearly that the Church and her Pastors are not opposed to true and solid science, whether human or divine, but that they embrace it, encourage it, and promote it with the fullest possible devotion.

Relations improved further when Pope Leo XIII, because of Italian considerations, distanced the Vatican from the Rome-Vienna-Berlin alliance, and helped to facilitate a rapprochement between Paris and St. Petersburg.

Under Otto von Bismarck, the anti-Catholic Kulturkampf in Prussia led to significant restrictions on the Catholic Church in the German Empire, including the Jesuits Law of 1872.

Leo XIII possessed a great affection for France, and feared that the Third Republic would take advantage of the fact that most French Catholics were Royalists to abolish the Concordat of 1801.

"[47] In 1892, Pope Leo XIII opened the Vatican archives to William Eleroy Curtis, a special envoy planning the commemoration of Christopher Columbus at the 1893 World's Columbian Exposition.

[48][49] Pope Leo XIII is remembered for the First Plenary Council of Latin America held at Rome in 1899, and for his encyclical of 1888 to the bishops of Brazil, In plurimis, on the abolition of slavery.

The outcome of this investigation was positive and so in the encyclical letter Annum sacrum (on 25 May 1899), he decreed that the consecration of the entire human race to the Sacred Heart of Jesus should take place on 11 June 1899.

He was greatly influenced by Wilhelm Emmanuel von Ketteler, a German bishop who propagated siding with the suffering working classes in his book Die Arbeiterfrage und das Christentum.

In 1899, Leo XIII hoped to nominate the Dominican procurator general Hyacinthe-Marie Cormier (later beatified) to the cardinalate; however, he was unable to do so because the French government did not favor a cardinal from a religious order to seek its best interests as a Curial member.

On a pilgrimage with her father and sister in 1887, Thérèse of Lisieux attended a general audience with Pope Leo XIII and asked him to allow her to enter the Carmelite order.

A common account says that on the morning of 13 October 1884, Leo XIII celebrated Mass but as he finished, he turned to step down the stairs and allegedly collapsed, falling into what was originally thought to be a coma, but was rather a mystical ecstasy.

[74] At the time of his election in 1878, the pope had started to experience a slight tremor in his hand due to a poorly undertaken bloodletting procedure for a previous malady.

While Leo XIII strongly rejected the notion of surgery at first, he was persuaded by Cardinal Mariano Rampolla del Tindaro that it was necessary to ensure his good health.

[7] On 30 June 1903, Leo XIII reported slight feelings of dyspepsia and said that he would take a dose of castor oil to help himself recuperate, shrugging off concerns about his health.

[76] The pope's nephews were immediately notified of their uncle's illness, as were Cardinals Mariano Rampolla del Tindaro and Luigi Oreglia di Santo Stefano in their capacities as the Secretary of State and Camerlengo respectively.

[87] However, although there is some contemporary documentation attesting to their ages, there is not sufficient evidence for them to be verified with complete certainty; this is due to the poor record keeping typical of the era in which they lived.