Historians’ self-censorship for political ends is a modern nationalist practice

Evidence

In pre-modern times, this is surprisingly rare. Historians on the whole tell it like it was. Occasionally, when they don’t, they confess. There are some striking passages in Tabari, for example, where he confesses in so many words to suppressing some information as not being in the public interest. For the most part, however, such suppression is a modern practice that arrives only with nationalism and nationalist historiography. — Bernard Lewis, From Babel to Dragomans, 1957