 Suárez was a student at Salamanca in 1561, when he joined the Society of Jesus. He was an educator, settling eventually in Coimbra, where he produced a tract De legibus ac Deo legislatore (1612). As a polemicist, he intervened in the quarrel over the oath of allegiance imposed by James I on English Catholics after the Gunpowder Plot (1605). Suárez and his Jesuit contemporary Robert Bellarmine were the most important Catholic writers on political and ecclesiological issues following the Council of Trent.