History textbooks are becoming more "sanitised" - ignoring some of Europe's bloodiest battles and struggles, a study suggests.
Never forget the Viking threat, says report
Even the raping and pillaging Vikings have had an image makeover, says Dr Yasemin Soysal, a sociologist at Essex University.
The study of European history had often become "curiously devoid of conflicts and cleavages" during the last 30 years, she added.
Dr Soysal said: "The Vikings are no longer seen as marauders, but as skilful traders enjoying cultural exchanges with far-flung populations.
"Heroes like Joan of Arc and Bismarck are not simply personifications of glorious national moments, but also appear as persons with ordinary weaknesses.
"Sir Francis Drake, for example, is portrayed as a good sailor, but also someone with avid desire for worldly possessions."
Dr Soysal, also president of the European Sociological Association, compared the content and style of history textbooks used by secondary school pupils in Germany, France, the UK and Turkey.
The research identified two major turning points in the teaching of history - the 1970s and the 1990s.
In the 1970s, the history of nations - which had been marked by wars, hardships and rivalry - was replaced by accounts of cultural exchanges, trade and the achievements of civilisation.
Timescales gave way to the presentation of themes, while individual heroes lost their mythical status.
At the same time, Dr Soysal found increased coverage of the 20th century at the expense of previous historical periods.
'Lack of time'
Then, in the 1990s, Europe became a textbook topic in its own right.
But this was as a set of abstract principles, such as democracy and human rights, which could be used to build the future.
However, apart from these ideas, there was no common understanding of what Europe meant, according to Dr Soysal.
She said: "Textbooks now increasingly place the nation and even regions within a European context.
"In German history books, for example, Europe and local regions figure prominently, while the nation itself disappears.
"In French textbooks, on the other hand, the French nation has a much stronger presence and Europe is commonly portrayed as French."
In the UK, where the national curriculum is a more recent innovation, the research found evidence of a more outward-looking European emphasis, particularly in the newly introduced subject of citizenship.
The general importance of teaching European history was widely accepted, but there were many obstacles to putting it into practice.
Dr Soysal said: "These include lack of time to teach Europe and its languages in classes, lack of guidance about how Europe should be taught and lack of power to give it compulsory status in syllabuses and exams."