went into decline for several centuries, followed eventually by a gradual rise in formal education, culminating in the rise of medieval universities. But rhetoric transmuted during this period into the arts of letter writing (ars dictaminis) and sermon writing (ars praedicandi). As part of the trivium, rhetoric was secondary to the study of logic, and its study was highly scholastic: students were given repetitive exercises in the creation of discourses on historical subjects (suasoriae) or on classic legal questions (controversiae). Although he is not commonly regarded as a rhetorician, St. Augustine (354–430) was trained in rhetoric and was at one time a professor of Latin rhetoric in Milan. After his conversion to Christianity, he became interested in using these "pagan" arts for spreading his religion. This new use of rhetoric is explored in the Fourth Book of his De Doctrina Christiana, which laid the foundation of what would become homiletics, the rhetoric of the sermon. Augustine begins the book by asking why "the power of eloquence, which is so efficacious in pleading either for the erroneous cause or the right", should not be used for righteous purposes (IV. 3). One early concern of the medieval Christian church was its attitude to classical rhetoric itself. Jerome (d. 420) complained, "What has Horace to do with the Psalms, Virgil with the Gospels, Cicero with the Apostles?" Augustine is also remembered for arguing for the preservation of pagan works and fostering a church tradition that led to conservation of numerous pre-Christian rhetorical writings. Rhetoric would not regain its classical heights until the Renaissance, but new writings did advance rhetorical thought. Boethius (480?–524), in his brief Overview of the Structure of Rhetoric, continues Aristotle's taxonomy by placing rhetoric in subordination to philosophical argument or dialectic. The introduction of Arab scholarship from European relations with the Muslim empire (in particular Al-Andalus) renewed interest in Aristotle and Classical thought in general, leading to what some historians call the 12th century Renaissance. A number of medieval grammars and studies of poetry and rhetoric appeared. Late medieval rhetorical writings include those of St. Thomas Aquinas (1225?–1274), Matthew of Vendome (Ars Versificatoria, 1175?), and Geoffrey of Vinsauf (Poetria Nova, 1200–1216). Pre-modern female rhetoricians, outside of Socrates' friend Aspasia, are rare; but medieval rhetoric produced by women either in religious orders, such as Julian of Norwich (d. 1415), or the very well-connected Christine de Pizan (1364?–1430?), did occur if not