FRANÇOIS D’AGUILON. - Belgian Jesuit, born in Brussels on 4 January 1567, he entered the novitiate in Tournai in 1586. Ordained priest in 1596, he spent the rest of his life at the college in Antwerp, where he taught theology, served as vice-rector, and later as rector; he died there on 2 May 1617.
He enjoyed a reputation as a skilled mathematician, especially for his major treatise *Opticorum Libri VI* (Antwerp 1613, in-folio, with fine engravings after designs by Rubens; reprinted in Würzburg in 1685 and in Nuremberg in 1702). The work was intended to comprise three volumes but remained incomplete. Particularly noteworthy is his study of projections, in whose terminology he introduced the term “stereographic projection.” He played a significant role in establishing, at the Jesuit college in Antwerp, a special school of mathematics, inaugurated in 1617 by the distinguished geometer Fr. Gregory of Saint-Vincent, which produced a modest body of work. D’Agulon also holds a place in art history: he designed the plans for the church of the professed house of the Jesuits in Antwerp (now S. Carlo Borromeo), one of the most important Baroque monuments in Belgium, though it is difficult to distinguish his contribution from that of the great artist Fr. Peter Huyssens, who assisted him and continued construction after the rector’s death.