Llull's eccentric logical machinery had a missionary purpose that is easy to lose. After his conversion at about thirty he set himself three aims and pursued them with total single mindedness for half a century: to write books against error, to found schools of languages, and to die a martyr. The second aim produced Miramar, the college he persuaded the king of Majorca to endow in 1276, where Franciscan friars were to learn Arabic before preaching in North Africa; Llull himself had learned Arabic over nine years from an enslaved Muslim tutor, and wrote some of his works in it first.
The Art, the system of lettered wheels and combinatoric tables for which he is remembered, was designed for exactly this frontier. Its premise is that argument from shared first principles, the dignities of God that Christian, Muslim and Jew all confess, goodness, greatness, eternity, power, wisdom, will, could proceed without appeal to any scripture the other side rejected. It was, in intention, a machine for debating across religions in terms both parties already accepted. He crossed to North Africa to dispute publicly at least three times, was expelled, imprisoned and stoned, and the tradition that he died of injuries received at Bougie in 1315 or 1316, though unverifiable in its details, fits the life he said he wanted. The combinatoric wheels that later fascinated Leibniz were, for their maker, mission equipment.