Iluro
Historic siteThe Roman city under Mataró was tiny — about eight hectares, roughly eleven football pitches. But it was laid out around 80–70 BC on the standard military grid of a cardo maximus running north–south and a decumanus maximus running east–west, and that geometry is still legible in the street plan of the old town two thousand years later.
A planned city, not a grown one
Iluro was founded on a natural promontory in the first century BC, in the coastal strip of Hispania Tarraconensis, and it was planned from the start rather than accreted over time. The two main axes crossed at right angles; the remaining streets ran parallel to them as cardines and decumani minores, dividing the town into blocks. The Via Augusta passed close by, and the sea was immediately below — the two facts that explain why anyone built here at all. Eight hectares made Iluro a modest place next to Tarraco or Barcino, but it was a functioning Roman municipium with a forum, baths and a coastal trade role.
How the grid disappeared
The third-century crisis hit Iluro as it hit Roman towns across the peninsula. Through the fourth century the pattern of urban and rural life in Catalonia reorganised itself, and coastal towns of Roman foundation tended to survive by shrinking and concentrating. By the end of the fifth century the streets laid out in 80–70 BC had effectively ceased to exist as a system; the population had pulled north, toward the forum area, abandoning the southern sector. What survived was not the plan but the site — occupation continued, and medieval Mataró grew back over the same ground, which is why the Roman city is now almost entirely under later buildings.
What you can actually see
Very little of Iluro is standing, and that shapes any visit. First-century BC baths have been documented within the old town, and excavation has repeatedly turned up structures during building work. The substantial visitable remains sit outside the ancient core: the Torre Llauder villa, about 1.25 km from the Roman town on the plain facing the sea, discovered in 1961 and open since 1988. Finds from the city itself — ceramics, late Roman amphorae, everyday material — are held and displayed by Mataró’s municipal museum at Can Serra. Treat Iluro as a layer to read rather than a monument to walk around.
The old-town grid
Walking the historic centre, the surviving right angles are the clearest trace of the Roman plan still available above ground.
Torre Llauder
The villa in Iluro’s territory, with mosaics, hypocaust and a full bath sequence — the one place the Roman period is genuinely visible.
Santa Maria basilica
Built on ground associated with earlier religious use, and the anchor of the medieval town that replaced Iluro.
There is no Roman quarter
Iluro is not a site with a gate and a ticket desk. Come for the museum and Torre Llauder; the city itself is buried.
Frequently asked questions
When was Iluro founded?
Around 80–70 BC, on a natural promontory on the Maresme coast, as a planned Roman town of roughly eight hectares.
Can Iluro be visited?
Not as a standing site. The Roman city lies under modern Mataró; the visitable remains are the Torre Llauder villa outside the old core.
What happened to the Roman street plan?
It broke down after the third-century crisis and had ceased to function by the late fifth century, as the population contracted toward the forum area.
Where are the finds from Iluro kept?
In the Mataró Museum, whose permanent display traces the town from Iluro through the medieval and modern periods.
Explore more of the Costa del Maresme
Iluro is one of many destinations on the CostaMap interactive map — browse beaches, villages, castles and viewpoints across the whole coast.
How this page is maintained. CostaMap is written and maintained by an AI editorial system built by ebizapple. Facts are drawn from primary sources — town halls, museums, port and heritage authorities and the Spanish archaeological record — and where sources disagree, we say so rather than smooth it over. Photographs marked as ours are taken on location. This page was last reviewed on 10 August 2026. Opening hours, prices and transport change; check the official source before you travel.