Mercier, Désiré Joseph (dāzērāˈ zhôzĕfˈ mârsēāˈ) [key], 1851–1926, Belgian churchman, cardinal of the Roman Catholic Church. He was ordained in 1874 and eight years later became professor of philosophy at the Univ. of Louvain, where, under the auspices of Pope Leo XIII, he organized an institute for the study of the teachings of St. Thomas Aquinas. He became a foremost leader in the 20th-century revival of interest in Thomistic scholasticism and in its integration with modern developments. He was made archbishop of Malines (1906) and cardinal (1907). Cardinal Mercier worked to secure greater cooperation between the Catholic clergy and the laity and to promote social well-being. In World War I, Cardinal Mercier became the spokesman of Belgian opposition to the German occupation, for which the Germans placed him under house arrest.
See his autobiography, Cardinal Mercier's Own Story (1920); biographies by H. L. Dubly (1928) and J. A. Gade (1934).