A Latin text Titi Lvcreti Cari De Rervm Natvra Liber Tertivs Titus Lucretius Carus (15 October 99 BC - c. 55 BC) was a Roman poet and philosopher. His only known work is the philosophical poem De rerum natura, a didactic work about the tenets and philosophy of Epicureanism, and which is usually translated into English as On the Nature of Things. Lucretius has been credited with originating the concept of the three-age system which was formalised from 1834 by C. J. Thomsen. Very little is known about Lucretius's life; the only certain fact is that he was either a friend or client of Gaius Memmius, to whom the poem was addressed and dedicated.