I've never taken this twinning business seriously: but I can think of a twinning which ought to be (but isn't) signed and sealed: Avignon and Exeter.
The Avignon Papacy has had a bad press; Petrarch was only one of those to leave behind him highly tendentious writings which have fastened upon the period when the Sovereign Pontiffs lived in Avignon a reputation for corruption and venality. But when Pam and I were there last year it completely stole our hearts. I developed a soft spot especially for John XXII. It was he who in fact launched upon the Western Church the cultus of the Blessed Sacrament: Exposition, Processions and all. He ordered the observance of Trinity Sunday; the bowing of the head at the Holy Names of Jesus and Mary; the ringing of what came to be regarded as the evening Angelus; the use of the prayer Anima Christi (of which he has been suspected of being the author). He promoted literati and encouraged the study of Greek and Latin grammar. He fostered the veneration of our Lady; the statue which he gave of our Lady 'All-powerful' still exists in the Cathedral at Avignon - of which he was bishop before he became Pope. You might well conclude, as I did, that he was one of the grandfathers of the Counter-Reformation.
But what's the Exeter connection? He 'provided' one of his close proteges and friends to be Bishop of Exeter - John de Grandisson (pronounced 'Grahns'n'), a member of a noble Burgundian family, who thus became one of the great builders of Exeter Cathedral and a patron of the arts so powerful that in a 1988 London exhibition he merited, despite the depredations of time and of the Tudors, a section of his own. He possessed a Hebrew grammar; he codified and reformed the usages of his Cathedral Church; manifested a fierce and protective devotion to the Mater Misericordiae and attempted to lure his Cathedral clergy to bow their heads at the mention of her name. He bequeathed to his Cathedral and to his foundation at Ottery monstrances which must count as two of the most splendid pieces of medieval metalwork of which we have detailed records.
And there is a mystery about John XXII of which I can't help feeling that Grandisson just might be the key. The pope's tomb in Avignon Cathedral is a superb piece of ... yes, English workmanship.
I'd recommend the splendours of Avignon as a holiday destination to anybody who likes Art, History, wine and food. I only wish somebody would subsidize us to go there again. If you do find yourself there, you could do worse than to worship on Sunday morning in the Chapel of the Black Penitents: an exquisitely baroque masterpiece which is served by the Society of S Pius X. Unlike so many French churches, it has a predominantly young congregation and you aren't 'conducted' in the music of the mass by a officious layperson or regaled with guitars. It's the next best thing to an Ebbsfleet church.