Rome followed Athens as the ancient world's leader in politics, the military and philosophy. As a young man in his 20s, Marcus Tullius Cicero, pleaded cases in the public forum during the first century B.C. This leading Roman orator, politician, lawyer and philosopher developed the five canons of rhetoric, which continues to be used in modern-day law courtrooms. The five canons include invention, arrangement, style, memory and delivery. In the second century A.D., the Roman Forum was built, which was used for public speaking.