The Matriz de Nossa Senhora da Imaculada Conceição does not read as a country chapel. It runs 33 metres long and 20 wide, with two square towers 20 metres high and a run of semicircular arches forming a covered walkway along the flank. The masonry is load-bearing brick — requeimado, reburnt, fired hard — and the whole thing carries itself without a frame. The word people reach for is fortress, and the sertão of the seventeenth century gave good reasons for that. IPHAN, Brazil's national heritage institute, listed the building in 1954. Stand in front of it and the chronology does the work: this church was finished a generation before the gold that would define everything the outside world thinks it knows about Minas Gerais.

Matias Cardoso de Almeida was born around 1605 and was still alive after 1704, which is a long career for the work he did. He came up on bandeiras out of São Vicente and Itanhaém, and by the 1660s he was regarded as one of the men who knew the routes between São Paulo and the southern interior. In 1673 he served as captain-major under Fernão Dias on the expedition that went looking for emeralds at Sabarabuçu, returning around 1680. What followed is harder to accommodate in a founder's statue. Through the 1680s and after, he led military expeditions against the Cariri and the Janduí in the Bahia and São Francisco sertão — campaigns that destroyed villages, killed the people in them, and delivered survivors into slavery and into forced resettlement in aldeamentos. Those were nations with their own territories, languages and claims to the river, and the settlement he founded was built on ground taken from them. Genealogies long recorded him as a pathfinder; the historians working on him now describe an agent of colonial violence, and the two portraits are of the same man. His son, Januário Cardoso de Almeida, went on to hold military posts along the same river.

The place began around 1660 under a different name — Morrinhos, the little hills — as a cluster of fazendas raising cattle in country too dry for much else. Cattle turned out to be the right bet. The São Francisco was the highway of the interior, and Morrinhos traded up it toward Salvador, prosperous enough within a decade to justify a church on the scale of the one that got built. Nearly four centuries later the ledger looks familiar: cattle first, with some 46,000 head counted in 2006, then cotton, peanuts, corn, manioc, sorghum, sugarcane and mamona, the castor oil plant. The river still runs past. The trade routes moved elsewhere.

People of this region call themselves geraizeiros, after the gerais — the open backlands that gave the state the second half of its name. They live with drought and thin soils, a long way from any large city, on a stretch of river that the twentieth century mostly routed around. In the 2000 census the municipality ranked 831st of 853 in Minas Gerais on the human development index, and the gaps in sanitation and schooling behind that number were wide. Matias Cardoso has only existed as a municipality since 1993; the 2022 census counted 8,895 people across 1,938 square kilometres, a population that has been shrinking. Inside its boundaries sits the 6,358-hectare Jaíba Biological Reserve, fully protected since 1994. Since 2011 the town has marked 8 December, the feast of the Immaculate Conception and the patronal day of that improbable old church, as the Day of the Gerais — a claim, made annually, that the history of Minas Gerais started out here on the river rather than in the goldfields.