Marcus Cocceius Nerva (November 8, 30 – January 27, 98) was a Roman Emperor who briefly reigned from 96 until his death in 98. Nerva acceded to this position at the advanced age of 65, after a lifetime of imperial service under emperor Nero and the rulers of the Flavian dynasty, Vespasian, Titus and Domitian. Under Nero, he was a member of the imperial entourage and played a vital part in exposing the Pisonian conspiracy of 65. Later, as a loyalist to the Flavians, he attained consulships in 71 and 90 during the reigns of Vespasian and Domitian respectively.
On September 18, 96, Domitian was assassinated in a palace conspiracy involving members of the Praetorian Guard and several of his freedmen. The same day, Nerva was declared emperor by the Roman Senate. As the new ruler of the Roman Empire, he vowed to restore liberties which had been curtailed during the autocratic government of Domitian, however Nerva's brief reign was marred by financial difficulties and his inability to assert his authority over the Roman army. A revolt by the Praetorian Guard in October of 97 all but forced him to adopt the more popular Marcus Ulpius Traianus—commonly known as Trajan—as his heir and successor. After not quite eighteen months in office, Nerva died of natural causes on January 27 98. Upon his death he was succeeded and deified by his adopted son Trajan.
Although much of his life remains obscure, Nerva was considered a wise and moderate emperor by ancient historians, a view which was later popularized by the 18th century scholar Edward Gibbon, who termed the rule of Nerva and his four successors as that of the Five Good Emperors, following similar comments by Machiavelli in the early 16th century. By adopting Trajan as his heir, Nerva is said to have established a tradition of succession through adoption among the emperors which followed. Recent historians, however, have revised these opinions.