John Hawks has a long post on ancient lifespans. It seems likely that the range has not shifted much, though the shape of the distribution naturally has. Child mortality has obviously declined, but it seems likely that death at any given age in adulthood has probably decreased as well. But for what it’s worth, several of the Roman Emperors from aristocratic backgrounds whose ages are probably reliable and died natural deaths expired at an advanced age. Augustus at 76, Tiberius at 77, Claudius 63 (there is debate whether he died a natural death), Vespasian 69, Nerva 67, Trajan 63, Hadrian 62, Antinuous Pius 74 and Marcus Aurelius 58. As most of you probably know, hell broke loose after Aurelius at many Emperors did not die of natural causes until the late 3rd century after his reign. Note that some of these Emperors, such as Nerva or Vespasian, were already at very advanced ages when they came to power, so there is probably some selection effect at work in terms of age at death. Vespasian’s son Titus died of fever at the age of 41.