DURING the greater part of this period, the lands of the Roman empire enjoyed on the whole a prosperity and peace unknown before and never experienced since. Literature continued to nourish in the first century A.D. Tacitus (about A.D. 55-117), the historian, wrote a bitter and brilliant account of the early years of the empire. Many of his mordant phrases have become familiar, such as " They make a desert and call it peace." Juvenal's caustic satires have found countless imitators. The letters of the Younger Pliny (about A.D. 61-113) to the Emperor Trajan, asking for advice on how to deal with the new sect of Christians, give a very fine picture of an over-conscientious official and an extremely able and wise emperor. The noble philosophy of Seneca (about 4 B.C.-A.D. 65) is illustrated in the sentences, " Love if you wish to be loved," and " What matters is not how long you live, but how well."