In 137 BC, the Roman general Decimus Junius Brutus crossed the Miño river — a boundary that the native Gallaeci considered inviolable. His campaign against the Celtic tribes of the northwest earned him the cognomen "Callaicus," and it marked the first time Roman legions penetrated the heartland of what would become Gallaecia. The crossing likely occurred near the middle Miño valley — the ancestral territory of the Querquerni and Coelerni tribes in what is now Ourense province. For the communities of Castrelo de Miño, Cartelle, and Ribadavia, this was the beginning of a transformation that would reshape every aspect of life.

Over a century of intermittent warfare followed. In 61 BC, Julius Caesar, then governor of Hispania Ulterior, launched a naval expedition to Brigantium (modern A Coruña), establishing Roman authority along the Atlantic coast. The decisive conquest came during the Cantabrian Wars (29–19 BC), when Augustus dispatched legions to subjugate the last free peoples of Iberia. The Gallaeci resisted fiercely — Strabo recorded that the women of the Gallaeci fought alongside the men, and mothers killed their own children rather than see them enslaved. By 19 BC, Rome controlled all of Gallaecia. The territory of the Querquerni around the Miño and Limia valleys was incorporated into the Conventus Bracarensis, administered from Bracara Augusta (modern Braga).

At the heart of the road system stood Ourense, known to the Romans as Aquae Urentes ("Scalding Waters") or Aquae Aurienses — named for the thermal springs of As Burgas that still pour steaming water at 67°C in the city center. The Romans recognized the springs' value immediately and developed them into public bathhouses — thermae — in the 1st and 2nd centuries AD. Bathing was central to Roman civic life: the baths were not merely places to wash but social institutions where citizens conducted business, exercised, and debated. In the provincial town of Aquae Urentes, the thermae anchored an emerging urban center on the Via Nova, drawing travellers, merchants, and administrators passing between Bracara Augusta and Asturica Augusta.

The thermal springs gave Ourense its identity and its name. The city grew from a modest way-station into a prosperous settlement, with a forum, markets, and residential quarters radiating outward from the baths. The proximity of As Burgas to the Miño crossing made Ourense the natural administrative hub for the surrounding territory — including the rural communities of Castrelo de Miño, Cartelle, and Ribadavia in the wine-rich valleys to the south. Today, the Burgas fountains still flow at their ancient temperature, a living link to the Roman city that rose around them.

Of all the changes Rome brought to the Miño valley, none proved more lasting than the vine. The Romans introduced systematic viticulture to Gallaecia, planting the sheltered river valleys with grape varieties and applying the winemaking techniques of the Mediterranean. The earliest physical evidence of this transformation was found at Castro de Santa Lucía in Astariz, a parish of Castrelo de Miño: a rock-cut wine press (lagar rupestre) dated to approximately 235 AD, discovered during University of Vigo excavations in 2016. This is the oldest known evidence of winemaking in the entire Ribeiro region — and it was found in the family's ancestral parish. The warm microclimate of the Miño, Avia, and Arnoia river valleys, with their granite soils and south-facing slopes, proved ideal for the vine. What the Romans planted would grow into the Ribeiro Denominación de Origen, one of the oldest and most celebrated wine regions in all of Spain.

Beyond the vine, Rome transformed the economy of the interior. The gold mines of Ourense province — worked through techniques including ruina montium (hydraulic mining) — fed the Imperial treasury. While the colossal Las Médulas in León was the largest Roman gold mine in the Empire, smaller but significant operations dotted the Ourense landscape, exploiting alluvial gold from the Sil and Miño rivers and their tributaries. Tin mining — the same cassiterite deposits that had drawn Phoenician traders centuries earlier — continued under Roman management on an industrial scale. The agricultural landscape was reshaped as well: Roman settlers and Romanized Gallaeci introduced new crops and techniques, established market-oriented farming along the road network, and began the transition from the subsistence agriculture of the castro period to the diversified farming of Roman villas.

Christianity arrived in Gallaecia during the later Roman centuries. By the 4th century, the faith had taken root, and the Council of Elvira (c. 305 AD) — which included bishops from Gallaecia — is the earliest recorded church council in Iberia. The Romanized tribal structure provided the framework for the first dioceses: Ourense, Braga, and Lugo became episcopal seats that endure to this day. In the late 4th century, Priscillian — bishop of Ávila, whose movement found its greatest following in Gallaecia — led a Christian reform movement that became the first heresy to result in a death sentence by secular authorities, evidence of how deeply Christianity had penetrated Galician society.

When the Suevi crossed the Pyrenees in 409 AD and established their kingdom in Gallaecia, they inherited a thoroughly Romanized landscape — Latin-speaking, Christian, connected by roads, cultivating vines in the Miño and Avia valleys, and organized into the administrative units that would become the parishes and municipalities of modern Galicia. The bridge crossings of the Miño still carried traffic. The thermal baths of As Burgas still steamed. The vineyards that the Romans had planted around Ribadavia and Castrelo de Miño still bore fruit. Rome's legions had departed, but the world they built endured — in the language spoken in the fields of Cartelle, in the wine pressed from the hillsides of the Ribeiro, in the parish church that would rise where a Roman altar once stood.