In historiography, historical revisionism is the reinterpretation of a historical account. It usually involves challenging the orthodox (established, accepted or traditional) views held by professional scholars about a historical event or timespan or phenomenon, introducing contrary evidence, or reinterpreting the motivations and decisions of the people involved. The revision of the historical record can reflect new discoveries of fact, evidence, and interpretation, which then results in revised history. In dramatic cases, revisionism involves a reversal of older moral judgments.
At a basic level, legitimate historical revisionism is a common and not especially controversial process of developing and refining the writing of histories. Much more controversial is the reversal of moral findings, whereby what mainstream historians had considered (for example) positive forces are depicted as negative. Such revisionism, if challenged (especially in heated terms) by the supporters of the previous view, can become an illegitimate form of historical revisionism known as historical negationism if it involves inappropriate methods such as the use of forged documents or implausible distrust of genuine documents, attributing false conclusions to books and sources, manipulating statistical data, and deliberately mistranslating texts. This type of historical revisionism can present a re-interpretation of the moral meaning of the historical record. Negationists use the term revisionism to portray their efforts as legitimate historical inquiry; this is especially the case when revisionism relates to Holocaust denial.
Historical revisionism is the means by which the historical record, the history of a society, as understood in its collective memory, continually accounts for new facts and interpretations of the events that are commonly understood as history. The historian and American Historical Association member James M. McPherson has said:
The fourteen-thousand members of this association, however, know that revision is the lifeblood of historical scholarship. History is a continuing dialogue, between the present and the past. Interpretations of the past are subject to change in response to new evidence, new questions asked of the evidence, new perspectives gained by the passage of time. There is no single, eternal, and immutable "truth" about past events and their meaning.
The unending quest of historians for understanding the past – that is, revisionism – is what makes history vital and meaningful. Without revisionism, we might be stuck with the images of Reconstruction [1865–77] after the American Civil War [1861–65] that were conveyed by D. W. Griffith's The Birth of a Nation  and Claude Bowers's The Tragic Era . Were the Gilded Age [1870s–1900] entrepreneurs "Captains of Industry" or "Robber Barons"?
Without revisionist historians, who have done research in new sources and asked new and nuanced questions, we would remain mired in one or another of these stereotypes. Supreme Court decisions often reflect a "revisionist" interpretation of history as well as of the Constitution.
In the field of historiography, the historian who works within the existing establishment of society and has produced a body of history books from which he or she can claim authority, usually benefits from the status quo. As such, the professional-historian paradigm is manifested as a denunciative stance towards any form of historical revisionism of fact, interpretation or both. In contrast to the single-paradigm form of writing history, the philosopher of science, Thomas Kuhn, said, in contrast to the quantifiable hard sciences, characterized by a single paradigm, the social sciences are characterized by several paradigms that derive from a "tradition of claims, counterclaims, and debates over [the] fundamentals" of research. On resistance to the works of revised history that present a culturally-comprehensive historical narrative of the US, the perspectives of black people, women, and the labour movement, the historian David Williams said:
These, and other, scholarly voices, called for a more comprehensive treatment of American history, stressing that the mass of Americans, not simply the power élites, made history. Yet, it was mainly white males of the power élite who had the means to attend college, become professional historians, and shape a view of history that served their own class, race, and gender interests at the expense of those not so fortunate – and, quite literally, to paper over aspects of history they found uncomfortable. "One is astonished in the study of history", wrote Du Bois in 1935, "at the recurrence of the idea that evil must be forgotten, distorted, skimmed over.... The difficulty, of course, with this philosophy is that history loses its value, as an incentive and [as] an example; it paints perfect men and noble nations, but it does not tell the truth".
After the Second World War, the study and production of history in the US was expanded by the G.I. Bill, which funding allowed "a new and more broadly-based generation of scholars" with perspectives and interpretations drawn from the feminist movement, the Civil Rights Movement, and the American Indian Movement. That expansion and deepening of the pool of historians voided the existence of a definitive and universally-accepted history, therefore, is presented by the revisionist historian to the national public with an history that has been corrected and augmented with new facts, evidence, and interpretations of the historical record. In The Cycles of American History (1986), in contrasting and comparing the US and the Soviet Union during the Cold War (1945–1991), the historian Arthur M. Schlesinger Jr. said:
... but others, especially in the United States.... represent what American historians call revisionism – that is readiness to challenge official explanations. No one should be surprised by this phenomenon. Every war in American history has been followed, in due course, by skeptical reassessments of supposedly sacred assumptions... for [historical] revisionism is an essential part of the process, by which history, through the posing of new problems and the investigation of new possibilities, enlarges its perspectives and enriches its insights.
Revisionist historians contest the mainstream or traditional view of historical events and raise views at odds with traditionalists, which must be freshly judged. Revisionist history is often practiced by those who are in the minority, such as feminist historians, ethnic minority historians, those working outside of mainstream academia in smaller and less known universities, or the youngest scholars, essentially historians who have the most to gain and the least to lose in challenging the status quo. In the friction between the mainstream of accepted beliefs and the new perspectives of historical revisionism, received historical ideas are either changed, solidified, or clarified. If over a period of time, the revisionist ideas become the new establishment status quo a paradigm shift is said to have occurred. The historian Forrest McDonald is often critical of the turn that revisionism has taken but admits that the turmoil of the 1960s America has changed the way history was written:
The result, as far as the study of history was concerned, was an awakened interest in subjects that historians had previously slighted. Indian history, black history, women's history, family history, and a host of specializations arose. These expanded horizons enriched our understanding of the American past, but they also resulted in works of special pleading, trivialization, and downright falsification.
Historians are influenced by the zeitgeist (spirit of the time), and the usually progressive changes to society, politics, and culture, such as occurred after the Second World War (1939–1945); in The Future of the Past (1989), the historian C. Vann Woodward said:
These events have come with a concentration and violence for which the term revolution is usually reserved. It is a revolution, or perhaps a set of revolutions for which we have not yet found a name. My thesis is that these developments will and should raise new questions about the past, and affect our reading of large areas of history, and my belief is that future revisions may be extensive enough to justify calling the coming age of historiography an "Age of Reinterpretation". The first illustration [the absence from U.S. history of external threats, because of geography] happens to come mainly from American history, but this should not obscure the broader scope of the revolution, which has no national limitations.
Developments in the academy, culture, and politics shaped the contemporary model of writing history, the accepted paradigm of historiography. The philosopher Karl Popper said that "each generation has its own troubles and problems, and, therefore, its own interests and its own point of view".
it follows that each generation has a right to look upon and re-interpret history in [their] own way.... After all, we study history because we are interested in it, and perhaps because we desire to learn something about our [contemporary] problems. But history can serve neither of these two purposes if, under the influence of an inapplicable idea of objectivity, we hesitate to present historical problems from our point of view. And we should not think that our point of view, if consciously and critically applied to the problem, will be inferior to that of a writer who naïvely believes... that he has reached a level of objectivity permitting him to present "the events of the past as they actually did happen".
As the social, political, and cultural influences change a society, most historians revise and update their explanation of historical events. The old consensus, based upon limited evidence, might no longer be considered historically valid in explaining the particulars: of cause and effect, of motivation and self-interest – that tell How? and Why? the past occurred as it occurred; therefore, the historical revisionism of the factual record is revised to concord with the contemporary understanding of history. As such, in 1986, the historian John Hope Franklin described four stages in the historiography of the African experience of life in the US, which were based upon different models of historical consensus.
The historian Deborah Lipstadt (Denying the Holocaust: The Growing Assault on Truth and Memory, 1993), and the historians Michael Shermer and Alex Grobman (Denying History: Who Says the Holocaust Never Happened and Why Do They Say It?, 2002), distinguish between historical revisionism and historical negationism, the latter of which is a form of denialism. Lipstadt said that Holocaust deniers, such as Harry Elmer Barnes, disingenuously self-identify as "historical revisionists" in order to obscure their denialism as academic revision of the historical record.
As such, Lipstadt, Shermer, and Grobman said that legitimate historical revisionism entails the refinement of existing knowledge about an historical event, not a denial of the event, itself; that such refinement of history emerges from the examination of new, empirical evidence, and a re-examination, and consequent re-interpretation of the existing documentary evidence. That legitimate historical revisionism acknowledges the existence of a "certain body of irrefutable evidence" and the existence of a "convergence of evidence", which suggest that an event – such as the Black Death, American slavery, and the Holocaust – did occur; whereas the denialism of history rejects the entire foundation of historical evidence, which is a form of historical negationism.
Some of the influences on historians that may change over time are the following:
Authors have challenged the traditional understanding of the fall of the Roman Republic, particularly regarding Julius Caesar's ascent to power and the role of his assassins. In his 2004 book, The Assassination of Julius Caesar: A People's History of Ancient Rome, Michael Parenti challenges the orthodoxy regarding the role of several actors, most notably Cicero, as well as Brutus and others, arguing that Caesar was assassinated not out of legitimate concern for the Republic's integrity, but rather out of political animosity due to Caesar's reformist goals and policies. So-called "Caesarians" remain in the minority, however, as Parenti notes.
As non-Latin texts, such as Welsh, Gaelic and the Norse sagas have been analysed and added to the canon of knowledge about the period, and as much more archaeological evidence has come to light, the period known as the Dark Ages has narrowed to the point that many historians no longer believe that such a term is useful. Moreover, the term "dark" implies less of a void of culture and law but more a lack of many source texts in Mainland Europe. Many modern scholars who study the era tend to avoid the term altogether for its negative connotations and find it misleading and inaccurate for any part of the Middle Ages.
For centuries, historians thought the Battle of Agincourt was an engagement in which the English army, overwhelmingly outnumbered four to one by the French army, pulled off a stunning victory, a version that was especially popularised by Shakespeare's play Henry V. However, recent research by Professor Anne Curry, using the original enrollment records, has brought into question this interpretation. Though her research is not finished, she has published her initial findings, that the French outnumbered the English and the Welsh only by 12,000 to 8,000. If true, the numbers may have been exaggerated for patriotic reasons by the English.
In recounting the European colonization of the Americas, some history books of the past paid little attention to the indigenous peoples of the Americas, usually mentioning them only in passing and making no attempt to understand the events from their point of view. That was reflected in the description of Christopher Columbus having discovered America. Those events' portrayal has since been revised to avoid the word "discovery."
In his 1990 revisionist book, The Conquest of Paradise: Christopher Columbus and the Columbian Legacy, Kirkpatrick Sale argued that Christopher Columbus was an imperialist bent on conquest from his first voyage. In a New York Times book review, historian and member of the Christopher Columbus Quincentenary Jubilee Committee William Hardy McNeill wrote about Sale:
McNeill declares Sale's work to be "unhistorical, in the sense that [it] selects from the often-cloudy record of Columbus's actual motives and deeds what suits the researcher's 20th-century purposes." McNeill states that detractors and advocates of Columbus present a "sort of history [that] caricatures the complexity of human reality by turning Columbus into either a bloody ogre or a plaster saint, as the case may be."
Historians in China and the West long wrote that the Manchus who conquered China and established the Qing dynasty (1636-1912) adopted the customs and institutions of the Han Chinese dynasties that preceded them and were "sinicized," that is, absorbed into Chinese culture. In the late 20th century, historians, especially in the West, explored Manchu language sources, explored newly accessible imperial archives, and discovered that the emperors retained their Manchu culture and that they regarded China proper as only one part of their larger empire. These scholars differ among themselves but agree on a major revision of the history of the Qing dynasty. 
The military historian James R. Arnold argues:
The writings of Sir Charles Oman and Sir John Fortescue dominated subsequent English-language Napoleonic history. Their views [that the French infantry used heavy columns to attack lines of infantry] became very much the received wisdom.... By 1998 a new paradigm seemed to have set in with the publication of two books devoted to Napoleonic battle tactics. Both claimed that the French fought in line at Maida and both fully explored French tactical variety. The 2002 publication of The Battle of Maida 1806: Fifteen Minutes of Glory, appeared to have brought the issue of column versus line to a satisfactory conclusion: "The contemporary sources are... the best evidence and their conclusion is clear: General Compère's brigade formed into line to attack Kempt's Light Battalion." The decisive action at Maida took place in less than 15 minutes. It had taken 72 years to rectify a great historian's error about what happened during those minutes.
After the proclamation of the Argentine Republic in late 1861, its first de facto President, Bartolomé Mitre, wrote the first Argentine historiographical works: Historia de Belgrano y de la Independencia Argentina and Historia de San Martín y de la emancipación sudamericana. Although these were criticised by notorious intellectuals such as Dalmacio Vélez Sarsfield and Juan Bautista Alberdi and even by some colleagues like Adolfo Saldías, both stated a liberal-conservative bias on Argentine history through the National Academy of History established in 1893, despite the existence of caudillos and gauchos.
During the Radical Civic Union government of Hipólito Yrigoyen, historians followed the revisionist view of anti-mitrist politicians such as Carlos D'Amico, Ernesto Quesada and David Peña and their theories reached the academy thanks to Dardo Corvalán Mendilharsu. Argentine historical revisionism could reach its peak during the peronist government. In 2011, the Manuel Dorrego National Institute of Argentine and Iberoamerican Historical Revisionism was established by the Secretary of Culture, but this one suffered a rupture between 21st century socialists and nationalists. Three weeks after the Inauguration of Mauricio Macri, the Institute was closed.
In reaction to the orthodox interpretation enshrined in the Versailles Treaty, which declared that Germany was guilty of starting World War I, the self-described "revisionist" historians of the 1920s rejected the orthodox view and presented a complex causation in which several other countries were equally guilty. Intense debate continues among scholars.
The military leadership of the British Army during World War I was frequently condemned as poor by historians and politicians for decades after the war ended. Common charges were that the generals commanding the army were blind to the realities of trench warfare, ignorant of the conditions of their men and unable to learn from their mistakes, thus causing enormous numbers of casualties ("lions led by donkeys"). However, during the 1960s, historians such as John Terraine began to challenge that interpretation. In recent years, as new documents have come forth and the passage of time has allowed for more objective analysis, historians such as Gary D. Sheffield and Richard Holmes observe that the military leadership of the British Army on the Western Front had to cope with many problems that they could not control, such as a lack of adequate military communications, which had not occurred. Furthermore, military leadership improved throughout the war, culminating in the Hundred Days Offensive advance to victory in 1918. Some historians, even revisionists, still criticise the British High Command severely but are less inclined to portray the war in a simplistic manner with brave troops being led by foolish officers.
There has been a similar movement regarding the French Army during the war with contributions by historians such as Anthony Clayton. Revisionists are far more likely to view commanders such as French General Ferdinand Foch, British General Douglas Haig and other figures, such as American John Pershing, in a sympathetic light.
Revisionist historians of the Reconstruction era of the United States rejected the dominant Dunning School that stated that Black Americans were used by carpetbaggers, and instead stressed economic greed on the part of northern businessmen. Indeed, in recent years a "neoabolitionist" revisionism has become standard, that uses the moral standards of racial equality of the 19th century abolitionists to criticize racial policies. "Foner's book represents the mature and settled Revisionist perspective", historian Michael Perman has concluded regarding Eric Foner's Reconstruction: America's Unfinished Revolution, 1863–1877 (1988).
The role of American business and the alleged "robber barons" began to be revised in the 1930s. Termed "business revisionism" by Gabriel Kolko, historians such as Allan Nevins, and then Alfred D. Chandler emphasized the positive contributions of individuals who were previously pictured as villains. Peter Novick writes, "The argument that whatever the moral delinquencies of the robber barons, these were far outweighed by their decisive contributions to American military [and industrial] prowess, was frequently invoked by Allan Nevins."
Prior to the collapse of the Soviet Union and the archival revelations, Western historians estimated that the numbers killed by Stalin's regime were 20 million or higher. After the Soviet Union dissolved, evidence from the Soviet archives also became available and provided information that led to a significant revision in death toll estimates for the Stalin regime, with estimates in the range from 3 million to 9 million.
The orthodox interpretation blamed Nazi Germany and Imperial Japan for causing the war. Revisionist historians of World War II, notably Charles A. Beard, said the United States was partly to blame because it pressed the Japanese too hard in 1940 and 1941 and rejected compromises. Other notable contributions to this discussion include Charles Tansill, Back Door To War (Chicago, 1952); Frederic Sanborn, Design For War (New York, 1951); and David Hoggan, The Forced War (Costa Mesa, 1989). The British historian A. J. P. Taylor ignited a firestorm when he argued Hitler was an ineffective and inexperienced diplomat and did not deliberately set out to cause a world war.
Patrick Buchanan, an American paleoconservative pundit, argued that the Anglo–French guarantee in 1939 encouraged Poland not to seek a compromise over Danzig. He further argued that Britain and France were in no position to come to Poland's aid, and Hitler was offering the Poles an alliance in return. Buchanan argued the guarantee led the Polish government to transform a minor border dispute into a major world conflict, and handed Eastern Europe, including Poland, to Stalin. Buchanan also argued the guarantee ensured the country would be eventually invaded by the Soviet Union, as Stalin knew the British were in no position to declare war on the Soviet Union in 1939, due to their military weakness.
The atomic bombings of Hiroshima and Nagasaki have generated controversy and debate. Historians who accepted President Harry Truman's reasoning in justifying dropping atomic bombs in order to force Japanese surrender end of World War II are known as "orthodox," while "revisionists" generally deny that the bombs were necessary. Some also claim that Truman knew they were not necessary but wanted to pressure the Soviet Union. These historians see Truman's decision as a major factor in starting the Cold War. They and others also may charge that Truman ignored or inflated predictions of casualties. 
Historians debate the causes and responsibility for the Cold War. The "orthodox" view puts the major blame on the Soviet Union, while a "revisionist" view puts more responsibility on the United States.
America in Vietnam (1978), by Guenter Lewy, is an example of historical revisionism that differs much from the popular view of the US in the Vietnam War (1955–75) for which the author was criticised and supported for belonging to the revisionist school on the history of the Vietnam War. Lewy's reinterpretation was the first book of a body of work by historians of the revisionist school about the geopolitical role and the US military behavior in of Vietnam.
In the introduction, Lewy said:
It is the reasoned conclusion of this study... that the sense of guilt created by the Vietnam war in the minds of many Americans is not warranted and that the charges of officially, condoned illegal and grossly immoral conduct are without substance. Indeed, detailed examination of battlefield practices reveals that the loss of civilian life in Vietnam was less great than in World War II [1939–45] and Korea [1950–53] and that concern with minimizing the ravages of the war was strong. To measure and compare the devastation and loss of human life caused by different war will be objectionable to those who repudiate all resort to military force as an instrument of foreign policy and may be construed as callousness. Yet as long as wars do take place at all it remains a moral duty to seek to reduce the agony caused by war, and the fulfillment of this obligation should not be disdained.— America in Vietnam (1979), p. vii.
Other reinterpretations of the historical record of the U.S. war in Vietnam, which offer alternative explanations for American behavior, included Why We Are in Vietnam (1982), by Norman Podhoretz, Triumph Forsaken: The Vietnam War, 1954–1965 (2006), by Mark Moyar, and Vietnam: The Necessary War (1999), by Michael Lind.
It is generally accepted that the foundations of modern chronology were laid by the humanist Joseph Scaliger. Isaac Newton in his work The Chronology of Ancient Kingdoms made one of the first attempts to revise the "Scaligerian chronology". In the twentieth century the "revised chronology" of Immanuel Velikovsky can be singled out in this direction, perhaps it initiated a wave of new broad interest in the revision of chronology. The materials of the "New Chronology", a proposed revision of eras by academician Anatoly Fomenko, albeit one widely rejected by mainstream scholars as pseudoscience, show many old historical images[example needed] with dates indicating the addition of a supplemental millennium in calendars in use in the Christian world a few centuries ago.[timeframe?][vague]
In general, many[who?] near-academic revisionist chronological theories suggest halving the duration of the Christian era, or consider certain historical periods to be erroneously dated, such as Heribert Illig's Phantom time hypothesis. At the same time, contemporary non-academic researchers often propose a more radical revision. For example, the model of chronology reconstruction of the revisionist Andrei Stepanenko reduces the entire known written history to several centuries. At the same time, other non-academic revisionists, thanks to publicly available sources, question the historical reliability of the person of Joseph Scaliger himself.
The ability to revise and update historical narrative – historical revisionism – is necessary, as historians must always review current theories and ensure they are supported by evidence. … Historical revisionism allows different (and often subjugated) perspectives to be heard and considered.