Quintilian was a prominent Roman educator and rhetorician who lived from 35 to 100 AD, best known for his influential work, 'Institutio Oratoria'. He focused on the art of rhetoric and the education of orators, stressing the importance of moral character in effective communication. His teachings laid the foundation for the study of rhetoric in both Ancient Rome and later periods, emphasizing that orators should not only be skilled in speaking but also virtuous in their actions.