Pope Leo XIII, born Gioacchino Vincenzo Raffaele Luigi Pecci on March 2, 1810, was the head of the Roman Catholic Church from February 20, 1878, until his death on July 20, 1903
. He had one of the longest papacies in history, serving for 25 years, the fourth longest after Peter the Apostle, Pius IX, and John Paul II
. Leo XIII is renowned for his intellectualism and efforts to reconcile the Catholic Church with modern ideas, including science and social issues. He promoted Thomism (the theological system of Thomas Aquinas) as the Church's foundation and issued the encyclical Aeterni Patris to revive this philosophy
. His 1891 encyclical Rerum Novarum is especially notable for addressing workers' rights, advocating for fair wages, safe working conditions, and the right to form trade unions, while balancing these with the rights to property and free enterprise. This made him known as the "Social Pope" and the "Pope of the Workers," laying the groundwork for modern Catholic social teaching
. Leo XIII also emphasized Marian devotion, issuing numerous encyclicals on the rosary and approving new scapulars, earning him the title "Rosary Pope"
. Politically, he sought to mitigate the loss of the Papal States and maintain the Church's influence despite the changing political landscape in Italy
. He was a reformer who improved the Church’s relations with civil governments, promoted education for clergy, and encouraged the coexistence of science and Christianity
. Leo XIII died at the age of 93 in Rome and was buried initially in the Vatican Grottoes, later moved to the Archbasilica of Saint John Lateran
. In summary, Pope Leo XIII was a significant figure who modernized the Catholic Church's approach to social issues, theology, and its role in the modern world while maintaining traditional doctrines
