MERCIER, DÉSIRÉ JOSEPH (1851–1926), a leading figure in Roman Catholic neoscholastic philosophy at the end of the nineteenth century and Cardinal Primate of Belgium (1906–1926). Born November 21, 1851, in Braine-l'Alleud, near Waterloo, Mercier studied philosophy and theology at Malines and earned a licentiate in theology at Louvain University (1877). Subsequently, he studied psychiatry in Paris.

Ordained a Roman Catholic priest in 1874, Mercier became a staunch supporter of Pope Leo XIII's call for a revival of Thomistic thought in the encyclical Aeterni patris (1879). Initially a professor of philosophy at the Malines seminary in 1877, Mercier then became the first holder of a new chair for Thomist philosophy at Louvain University in 1882. He soon sought papal approbation for a new institute at Louvain, and in 1889 Leo XIII approved the Institut Supérieur de Philosophie with Mercier at its head. Calling...