Tacitean studies
Tacitean studies, centred on the work of Tacitus, the ancient Roman historian, constitute an area of scholarship extending beyond the field of history. The work has traditionally been read for its moral instruction, its narrative, and its inimitable prose style; Tacitus has been most influential as a political theorist, outside the field of history. The political lessons taken from his work fall roughly into two camps : the "red Tacitists", who used him to support republican ideals, and the "black Tacitists", those who read his accounts as a lesson in Machiavellian realpolitik.
Though his work is the most reliable source for the history of his era, its factual accuracy is occasionally questioned: the Annals are based in part on secondary sources of unknown reliability, and there are some obvious minor mistakes. The Histories, written from primary documents and personal knowledge of the Flavian period, is thought to be more accurate, though Tacitus's hatred of Domitian seemingly colored its tone and interpretations.
Antiquity and Middle Ages
Tacitus's contemporaries were well-acquainted with his work; Pliny the Younger, one of his first admirers, congratulated him for his better-than-usual precision and predicted that his Histories would be immortal: only a third of his known work has survived and then through a very tenuous textual tradition; we depend on a single manuscript for books I–VI of the Annales and on another one for the other surviving half and for the five books extant of the Historiae. His books were clearly used by 2nd – early 3rd century historians such as Cassius Dio's report on Agricola's exploration of Britain, and Hegesippus may have borrowed from his account of the First Jewish–Roman War. His difficult historical methods and elliptic literary style, however, went unimitated except by Ammianus Marcellinus, who consciously set out to write a continuation of his works. His popularity waned with time: his unfavorable portrayals of the early emperors could not have earned him favor with Rome's increasingly autocratic rulers, and his obvious contempt for Judaism and Christianity made him unpopular among the early Church Fathers. The 3rd-century writer Tertullian, for example, blames him for originating the story that the Jews worshipped a donkey's head in the Holy of Holies and calls him "ille mendaciorum loquacissimus", 'the most loquacious of liars'.Image:Einhard.jpg|thumb|Monks like Einhard were the only readers of Tacitus for most of the Middle Ages.
In the 4th century there are scattered references to his life and work. Flavius Vopiscus, one of the supposed Scriptores Historiae Augustae, mentions him twice and names him among the disertissimi viri, the most eloquent men. Ammianus Marcellinus, as mentioned, started his history where Tacitus had finished. Jerome knew of him, and Sulpicius Severus either used his Annales as a source for passages on Nero or, according to Aurthur Drews, the passage in Sulpicius Severus's Chronicles later found its way into Annales. By the 5th century only a few authors seem aware of him: Sidonius Apollinaris, who admires him, and Orosius, who alternately derides him as a fool and borrows passages from his works. Cassiodorus and his disciple Jordanes make the last known antique references; Cassiodorus draws on parts of the Germania and Jordanes cites the Agricola, but both know the author only as Cornelius.
After Jordanes, Tacitus disappeared from literature for the better part of two centuries, and only four certain references appear until 1360. Two come from Frankish monks of the Carolingian Renaissance: the Annales Fuldenses from the monastery of Fulda used Tacitus's Annals, and Rudolf of Fulda borrowed from the Germania for his Translatio Sancti Alexandri. Some of Tacitus's works were known at Monte Cassino by 1100, where the other two certain references appear: Peter the Deacon's Vita Sancti Severi used the Agricola, and Paulinus Venetus, Bishop of Pozzuoli, plagiarized passages from the Annals in his mappa mundi. Hints and reminiscences of Tacitus appear in French and English literature, as well as German and Italian, from the 12th to the 14th century, but none of them is at all certain. It was not until Giovanni Boccaccio brought the manuscript of the Annals 11–16 and the Histories out of Monte Cassino to Florence, in the 1360s or 1370s, that Tacitus began to regain some of his old literary importance. His Annals survive only in single copies of two halves of the works, one from Fulda and one from Cassino.
Italian Renaissance
Boccaccio's efforts brought the works of Tacitus back into public circulation—where they were largely passed over by the Humanists of the 14th and 15th centuries, who preferred the smooth style of Cicero and the patriotic history of Livy, who was by far their favorite historian. The first to read his works—they were four: Boccacio, Benvenuto Rambaldi, Domenico Bandini, and Coluccio Salutati—read them solely for their historical information and their literary style. On the merits of these they were divided. Bandini called him " most eloquent orator and historian", while Salutati commented:For what shall I say about Cornelius Tacitus? Although a very learned man, he wasn't able to equal those closest . But he was even way behind Livy—whom he proposed to follow—not only in historical series but in imitation of eloquence.
Image:Leonardo Bruni 2.jpg|thumb|upright|Leonardo Bruni, the first to use Tacitus as a source for political philosophy
The use of Tacitus as a source for political philosophy, however, began in this era, triggered by the Florentine Republic's struggle against the imperial ambitions of Giangaleazzo Visconti. Visconti's death from an illness did more than lift his siege of Florence; it sparked Leonardo Bruni to write his Panegyric to the City of Florence, in which he quoted Tacitus to buttress his republican theory that monarchy was inimical to virtue, nobility, and genius. The inspiration was novel—Bruni had probably learned of Tacitus from Salutati. The thesis likewise: Tacitus himself had acknowledged that the good emperors Nerva and Trajan posed no threat to his endeavors.
Tacitus, and the theory that Bruni based on him, played a vital role in the spirited debate between the republicans of Florence and the proponents of monarchy and aristocracy elsewhere. Guarino da Verona, in 1435, used the literary flowering of Augustus's era—which included Livy, Horace, Virgil, and Seneca—to argue against Bruni's contention; Gian Francesco Poggio Bracciolini countered with the argument that all the authors had been born during the waning years of the Roman Republic. Pier Candido Decembrio, a Milanese courtier, addressed the same argument to Bruni in the following year, which Bruni did not bother to rebut, the best counterargument having been made already. The rule of Cosimo de Medici, however, saw the end of these political readings of Tacitus, though his works were now readily available in the public library of Florence. Instead, scholars such as Leone Battista Alberti and Flavio Biondo used him in academic works on the history and architecture of 1st century Rome. His laconic style and bleak outlook remained unpopular.
Image:Santi di Tito - Niccolo Machiavelli's portrait headcrop.jpg|thumb|upright|Niccolò Machiavelli resembles Tacitus in his pessimistic realism, but he himself preferred Livy.
At the beginning of the 15th century, following the expulsion of the Medici from Florence, their return, and the foreign invasions of Italy, Tacitus returned to prominence among the theorists of classical republicanism. Niccolò Machiavelli was the first to revive him, but not in the republican model which Bruni and others had followed. One quotation from the Annals appears in The Prince, advising the ruler that "it has always been the opinion and judgment of wise men that nothing can be so uncertain or unstable as fame or power not founded on its own strength". The idealized Prince bears some resemblance to Tacitus's Tiberius; a few have argued that Machiavelli had made more use of Tacitus than he let on. In fact, though, Machiavelli had probably not read the first books of the Annals at that time—they were published after The Prince.
In his work focused mainly on republicanism, Discourses on the First Ten Books of Livy, Machiavelli returned to Bruni's republican perspective on Tacitus. Four overt references appear in the work. Chapter follows Tacitus, and Bruni, on the chilling effects of monarchy. Chapter quotes the Histories on the burden of gratitude and the pleasure of revenge. Chapter quotes Tacitus: "men have to honor things past but obey the present, and ought to desire good Princes, but tolerate the ones they have". twists a line from Tacitus into something very similar to Machiavelli's famous maxim that it is better for a prince to be feared than loved. Many covert references appear: Machiavelli generally follows Tacitus's decidedly negative slant on the history of Rome under the Emperors.
Image:Tacito español.jpg|thumb|upright|Tácito español ilustrado con aforismos por Baltasar Álamos de Barrientos, en Madrid, por Luis Sánchez, 1614
Machiavelli had read Tacitus for instruction on forms of government, republican as well as autocratic, but after his books were placed on the Index Librorum Prohibitorum, writers on political philosophy frequently used the Roman as a stand-in for the Florentine, and the Emperor Tiberius as a mask for Machiavelli's model of a prince. So, writers like Francesco Guicciardini considered Tacitus's work to be an instruction on how to build a despotic state. Following that line of thought, the thinkers of the Counter-Reformation and the age of absolute monarchies used his works as a set of rules and principles for political action.
In the late 16th century Tacitus came to be regarded as the repository of the “secrets of the power”. Tacitus's description of the artifices, stratagems, and utterly lawless reign of power politics at the Roman imperial court fascinated European scholars. By the first half of the seventeenth century editions of and commentaries upon Tacitus were flourishing. The Roman historian was compulsory reading in the political education of any learned man, notably senior magistrates. While authors like Casaubon and Pasquier deemed the precepts of Tacitus pernicious, writers like Justus Lipsius, Scipione Ammirato and Baltasar Alamos de Barrientos set out their reason of state in the form of commentaries on his work. Even the Jesuit political philosopher Giovanni Botero, who put together Tacitus with Machiavelli as the leading authorities for those who advocated an amoral reason of state, was thoroughly acquainted with the work of the Roman historian.
Gerolamo Cardano in his 1562 book Encomium Neronis describes Tacitus as a scoundrel of the worst kind, belonging to the rich senatorial class and always taking their side against the common people.