Some societies are better at manipulation than others.
Certain events, individuals, ideas are either omitted or reworked so that those who are alive now are fed the ‘redacted’ version.
Most people do not know this. Do not even imagine certain events occurred.
Nations that became Independent or into Existence since 1950 have the added benefit of persons still alive who were ‘there’, who ‘know’ what happened.
Once history goes back over 100 years, it is reliance on records, for no one knows what ‘really’ happened.
Events that have occurred once television and radio were in use are more difficult to ‘erase’, for the record is there.
History before 1930, for example, can be ‘rewritten’ or ‘omitted’ or ‘ignored’ so that those in authority can put their spin on what is known, and pretend ignorance of those ‘side matters.’
As has been said; “History belongs to the Victors.” It also is the property of those who hold power at the time.