Sententiae (plural Latin form) are brief moral sayings, such as proverbs, adages, aphorisms, maxims, or apophthegms taken from ancient or popular or other sources, often quoted without context. A sententia (singular), also called a "sentence," is a kind of rhetorical proof. That is, if, in the midst of your presentation or conversation you say an old proverb or well-known quotation or especially witty or apt turn of phrase, you may be able to gain more easily the assent of your listener, who will hear a kind of non-logical, but agreed-upon "truth" in what you are saying. The use of sententiae is explained by Aristotle (Rhetoric 2.21 [1394a19ff], where he discusses the gnomê, or sententious maxim, as a form of enthymeme) and Quintilian (Institutes of Oratory, 8.5) amongst other classical authorities. Heavily influenced by humanist educational practices that encouraged the harvesting and use of commonplaces, or short quotable passages, early modern English writers were especially attracted to sententiae. The technique of sententious speech is exemplified by Polonius' famous speech to Laertes in Hamlet (Act 1, scene 3). Sometimes in Elizabethan and Jacobean drama the sententious lines appear at the end of scenes in rhymed couplets (for instance, John Webster's Duchess of Malfi). In some early modern dramatic texts and other writings, sententiae are often flagged by marginal notes or special marks (see G.K. Hunter, "The Marking of Sententiæ in Elizabethan Printed Plays, Poems, and Romances," The Library 5th series 6 (1951): 171-188).