AERNOULDT (ARNOULT), PIERRE. — Belgian Jesuit and ascetical writer, b. 17 May 1818 at Moere (West Flanders), d. at Cincinnati on 28 July 1865. Having gone to Missouri, he entered the Society of Jesus there in 1835. Professor in various colleges, then spiritual director and preacher of retreats, he owes his fame to his vigorous and pious work, *De Imitatione S.S. Cordis Iesu* by P. Arnoldi; written in 1848, it was published only in 1863 at Einsiedeln, but soon had very many editions and translations (Italian ones in Turin 1872 and in Rome 1940).
Bibl.: Sommervogel, I, 563-65; biographical notices at the head of the various translations of *Imitatione del S. Cuore*; P. H. Kelly, s. V. in *The Cath. Enc.*, I, pp. 750-51; G. J. Garrahan, *The Jesuits of the Middle United States*, II, New York 1938, pp. 105-107.