Dominic Cummings, chief adviser to the Prime Minister, thinks that there is no ‘better book than Thucydides as training for politics’. But what does he ‘teach’? His ‘lessons’ are legion. Herewith some possibilities.

In his history of the war between Athens and Sparta (430-404 bc), in which he briefly participated, smart one-liners leap off the page: ‘Humans are dominated by three motives: honour, fear and advantage’; ‘Identity of interests is the surest bond between states and individuals’; ‘Men consider what is pleasant to be honourable and what is advantageous, just’; and so on.