Tacitus is the most important historian the Roman world produced and one of the most important historians in any tradition. He is also, unmistakably, a man writing under conditions that shaped his account in ways he could not always control and occasionally did not try to. He was a senator who served the emperors he despised, a man who had survived Domitian’s reign by keeping his head down and who never entirely forgave himself for it, and who wrote history as an act of witness and accusation that the dead and the living were equally subject to. His prose style — compressed, ironic, capable of saying in a subordinate clause what lesser writers would require a paragraph — has influenced historical writing ever since and is the primary source for everything popular culture believes about Tiberius, Caligula, Nero, and their courts.