The Occitan word for stranger is estranhièr – a hauntingly beautiful word. And the broad swathe of Mediterranean coastline from Nîmes to the Spanish border has certainly been strongly influenced by successive waves of foreigners passing through, many never really leaving. The Greeks arrived in 600 BC bringing vines and wine; the Romans stayed for 400 years, leaving aqueducts, an amphitheatre, temples and roads; the Visigoths hung around Toulouse for many years; Louis IX decided that the Languedoc belonged to him; then came the Cathars, leaving their deliberately inaccessible castles such as this one. Of course,...