I'm reading this book at the moment, and I came across this quote from Gibbon's The History of the decline and fall of the Roman Empire (which I haven't read myself):
"If a man (sic) were called to fix the period in the history of the world during which the condition of the human race was most happy and prosperous, he would, without hesitation, name that which elapsed from the death of Domitian [AD 180]. The vast extent of the Roman empire was governed by absolute power, under the guidance of virtue and wisdom. The armies were restrained by the firm and gentle hand of four successive emperors, whose characters and authority commanded involuntary respect. The forms of the civil administration were carefully preserved by Nerva, Trajan, Hadrian and the Antonines, who delighted in the image of liberty, and were pleased with considering themselves as the accountable ministers of the laws."
[cited in Watson, p 294]
I don't think many people would agree with Gibbon nowadays (and with good reason), though I'm not sure how much better we're doing at the moment.