Does anyone know of any historical/mythological/ literary incidents of insincerity/deception? In particular incidents of “strategic” or “tactical” insincerity, where it is consciously made use of in order to realize long-term goals.
I am particularly interested in the classical antiquity (Ancient Rome and Greece).
I'm sorry, but we do not allow broad questions in this subreddit. If you have a specific question that you can place within a specific time period, you are free to ask. :)
Ruse de guerre is the term you're looking for.
I would recommend reading The Prince by Machiavelli. Most of the anecdotes are from the middle ages, but I seem to recall a few that are older than that. Also Sun Tzu's Art of War could be of interest to you, though again not classical european period.