President Obama was assailed for saying that the USA had no strategy on combating Isis. Vegetius (late 4th century AD), the author of the only surviving Roman treatise on military science, would have approved, since ‘no plans are better than those you carry out without the enemy’s knowledge in advance’. Indeed, he went so far as to argue that the reason why the Minotaur was depicted on legions’ standards was because ‘he was hidden away in the innermost and most secret labyrinth’.