In the first episode of BBC’s Civilisation from 1969, still intensely watchable, Kenneth Clark sits below a Roman aqueduct wearing a very English suit, citing Cavafy. He has just asked what civilisation’s enemies are. He gives a threefold answer: fear, boredom, and hopelessness, ‘which can overtake people with a high degree of material prosperity’. That’s where Cavafy’s Waiting for the Barbarians comes in. In it the poet evokes a late antique city in a state of apathy, every day awaiting the arrival of barbarian hordes expected to turn life upside down. In the end, though, the barbarians don’t turn up; they have directed their course elsewhere. The city’s inhabitants respond with spontaneous disappointment. Cataclysm would have been better than nothing. ‘Now what’s going to happen to us without barbarians?/Those people were a kind of solution.’ For a civilisation to thrive, says Clark, it needs, above all, confidence: the sense that life is worth living, that children are worth having, that the future is worth constructing. That’s every bit as true today as 53 years ago. Only, since then our store of confidence has shrunk.