Mid-First century marble bust of the Roman statesman, advocate, orator and writer Marcus Tullius Cicero. Cicero is best known for his philosophical writings which introduced Greek philosophy to ancient Rome. His essays are a source of information on the end of the Roman Republic and Julius Caesar's rise to power. Cicero witnessed the murder of Caesar and, in the power struggles that followed, he himself was murdered. His writings tell of his Greek friend Poseidonius, who had made a globe showing the movements of the Sun, stars and planets. During the first century BC, sculptors produced realistic and recognisable portraits intended to project the personalities of the subjects and the virtues valued in the Republican period.