But rhetoricians also viewed "memoria" as requiring more than just rote memorization. Rather, the orator also had to have at his command a wide body of knowledge to permit improvisation, to respond to questions, and to refute opposing arguments. Where today's speech-making tends to be a staged, one-way affair, in former times, much oration occurred as part of debates, dialogues, and other settings, in which orators had to react to others. Moreover, rhetoricians also recognized that the credibility of a speaker depended not just on the strength of his prepared arguments, but on the audience's perceptions of the speaker. In Greece, Rome, and the Renaissance, a speaker's familiarity of many areas of learning was seen as a virtue.