I. Azulejo, from the Arabic al-zulayj: the little polished stone. The Ferreira family have been pressing, glazing and painting that word outside Coimbra since 1732, nine generations of it, in a workshop that was a granary before it was anything else and has kept the granary’s manners – low beams, whitewashed walls gone the colour of weak tea, and at the centre of everything, squat, scorch-mouthed, older than every living Ferreira and consulted like one, the kiln. Begin with the kiln. The family does. Everything here follows from it.

II. Duarte Ferreira is sixty-one, ninth of the line, and technically a duke of nothing: Portugal retired its hereditary titles in 1910, and the family letterhead has simply declined to receive the news. ‘We kept the crest,’ he says, wiping cobalt paste from his thumb with a rag gone soft from several thousand performances of that one duty. ‘Nobody asked us to stop.’ He says it the way other men mention a subscription they forgot to cancel – without defiance, without embarrassment, without anything at all except the durable fact.

III. His great-great-grandfather raised the kiln by hand, and in the century since, no engineer has been permitted near it, because an engineer would cure it of its single genius. ‘An engineer would make it efficient. Efficient kilns fire evenly. Ours doesn’t. That’s how you get the variation people pay extra for now, without ever admitting that’s what they’re paying for.’ Flaw as signature; accident as inheritance; the fire keeping the family’s handwriting. I have paid extra for that variation myself, and sat there feeling gently and accurately fleeced.

IV. The business nearly died twice – the 1970s once, once after 2008 – and both times the remedy was the same, and it is older than the workshop: paint more slowly, eat rather less, ‘and wait for the country to remember it liked beautiful things again.’ The country remembered. It required several governments, two currencies, and outlasting, in his father’s day, one bruising Belgian tile importer whose name Duarte will not speak. I fished for it once. The look I received buried the question where questions go, permanently.

V. The painting room holds its silence the way a church does. Four apprentices beneath a skylight yellowed by decades of kiln smoke, the light arriving through that amber the way it arrives through old varnish, and no sound anywhere but breath and bristle. One boy is correcting a painted stem no wider than a hair, and nobody watches him except Duarte, and Duarte watches him the way the kiln watches the fire: with an attention so old it no longer needs expressing, and is therefore never, ever absent.

VI. ‘You cannot rush the blue,’ Duarte says, still watching. ‘It forgives nothing. If your hand shakes at fifty, it shook at twenty too. We just notice it more.’ The blue as ledger, then: every tremor entered, nothing written off, the body’s whole history called in through the wrist at last. He lifts a finished tile, turns it once in the light, sets it down, and says nothing whatever about it. In that room the silence is the wage. The boy has just been paid, and knows it.

VII. Lunch is bread, olives, and a fish stew his wife made that morning, at a long table scarred with decades of tile-glue rings – a table never once asked to look presentable for a photograph, and handsomer for the neglect. Over the stew, unprompted, comes the family’s true hallmark, stamped deeper than any crest. In 1958 a fascist minister wanted tile for his country house, and Duarte’s grandfather refused him, on grounds requiring no politics: ‘The pattern he wanted was ugly, and we don’t paint ugly things, whoever is asking.’

VIII. Afterwards, over coffee too strong to be entirely sociable, the order book: kept by hand since the 1800s, every commission entered not by client but by pattern, ‘because the pattern outlasts whoever ordered it, generally speaking, and it seemed rude to keep pretending otherwise.’ Three cathedrals are currently waiting on this one room for restoration tile. Private clients too – names on no invoice – wait longer and pay more, he implies without confirming, for the silence. Discretion prices the same in Coimbra as in Mayfair. Here it comes fired unevenly, deliberately.

IX. On the workshop windowsill sits a small blue-and-white tile, cracked cleanly in two, there longer than anyone living can remember, its painter unknown and now unknowable. Duarte shows it last, and returns it precisely to the clean patch its years have made. ‘Perhaps that’s the point of a family business. Eventually nobody needs to remember whose it was. Only that it stayed.’ The crack does not diminish it. The crack is the provenance. You may now stop looking for this panel’s broken tile. You are reading it.

X. I drove down through the olives with cobalt dust on my sleeve – signed, then, lightly, the way everything leaving that workshop is signed – wondering when a family stops being the makers of a thing and becomes its keepers, and whether the difference survives inspection. It does not. The kiln fires unevenly; the blue forgives no hand; the pattern outlives the name that ordered it; the cracked tile keeps its sill. Eighty-eight words, ten times, one crack. The mould holds. The mould held for the Ferreiras too.