Perhaps the most enduring legacy propaganda has upon the historical record is the destruction of documents. As Konrad Zuse said "One can adjust for the political slanting of the news, but there is virtually no way to fill in the omissions."
https://www.azquotes.com/quote/892699

For example, in 'Operation Legacy', the British government ordered the destruction of any documents that might "might embarrass Her Majesty's government". The quantity of documents thus destroyed was so great that several officials expressed concerns that they might not be able to destroy them all in times and lorries had to be borrowed from the army.
https://www.theguardian.com/uk-news/2013/nov/29/revealed-bonfire-papers-empire

The justification for the Iraq war was heavily based upon the claim that Saddam possessed chemical Weapons of Mass Destruction (WMDs). After the war ended, Iraq was searched by UN and US investigators for these WMDs but never found any. The US eventually fudged the matter by saying that some of Saddam's remarks had led his aids to believe that he was going to restart his chemical weapons program.[1]

The report of the UK government, nicknamed the 'dodgy dossier', was later revealed to have a large number of flaws including being based upon a source who MI6 was aware got his description of chemical weapons from the film 'The Rock' [2] and outright fabricating information to match one of US President Bush's claims. [3]

[1] https://www.theguardian.com/world/2004/oct/07/usa.iraq1
[2] https://www.telegraph.co.uk/news/2016/07/06/mi6-iraq-nerve-gas-report-stolen-from-action-film-the-rock/
[3] https://www.theguardian.com/uk/2010/jan/10/alastair-campbell-iraq-dossier-inquiry

The song is about a mighty and ancient dragon who rises into the firmament (heaven) to become a bright star.