that provided the orator with the forms, means, and strategies for persuading an audience of the correctness of the orator's arguments. Today the term rhetoric can be used at times to refer only to the form of argumentation, often with the pejorative connotation that rhetoric is a means of obscuring the truth. Classical philosophers believed quite the contrary: the skilled use of rhetoric was essential to the discovery of truths, because it provided the means of ordering and clarifying arguments. Sophists In Europe, organized thought about public speaking began in ancient Greece. Possibly, the first study about the power of language may be attributed to the philosopher Empedocles (d. c. 444 BC), whose theories on human knowledge would provide a newfound basis for many future rhetoricians. The first written manual is attributed to Corax and his pupil Tisias. Their work, as well as that of many of the early rhetoricians, grew out of the courts of law; Tisias, for example, is believed to have written judicial speeches that others delivered in the courts. Teaching in oratory was popularized in the 5th century BC by itinerant teachers known as sophists, the best known of whom were Protagoras (c. 481–420 BC), Gorgias (c. 483–376 BC), and Isocrates (436–338 BC). Aspasia of Miletus is believed to be one of the first women to engage in private and public rhetoric activities as a Sophist. The Sophists were a disparate group who travelled from city to city, teaching in public places to attract students and offer them an education. Their central focus was on logos or what we might broadly refer to as discourse, its functions and powers. They defined parts of speech, analyzed poetry, parsed close synonyms, invented argumentation strategies, and debated the nature of reality. They claimed to make their students "better", or, in other words, to teach virtue. They thus claimed that human "excellence" was not an accident of fate or a prerogative of noble birth, but an art or "techne" that could be taught and learned. They were thus among the first humanists. Several sophists also questioned received wisdom about the gods and the Greek culture, which they believed was taken for granted by Greeks of their time, making them among the first agnostics. For example, they argued that cultural practices were a function of convention or nomos rather than blood or birth or phusis. They argued even further that morality