A CAPITAL, NOT A RUIN
Salona: Inside Rome's Capital of the Province of Dalmatia
How big Salona really was, what a provincial capital's forum and theatre looked like, and the aqueduct whose water source still supplies Split today.
See Salona tours on GetYourGuide ↗A province the size of the Balkans
Roman Dalmatia wasn't a modest coastal strip — the province stretched deep into the western Balkans, and Salona sat at its administrative head as governor's seat and regional capital. That made it the hub through which taxes, legal disputes, military logistics and imperial correspondence for a huge stretch of territory passed, not merely a coastal trading town. Founded as a Roman colony in the 1st century BC on top of an earlier Illyrian and Greek settlement, Salona grew fast once it took on capital status, absorbing the administration, wealth and building programmes that came with governing a province. Understanding Salona as a seat of government, rather than a leftover ruin, reframes everything else on the site: the walls, the forum and the amphitheatre were built at the scale of a capital, not a market town.
How big was Salona, really?
Population figures for ancient cities are notoriously hard to pin down, and Salona is no exception — estimates vary widely depending on the source and what area is counted as "the city," but figures in the tens of thousands, sometimes cited as high as 40,000 or more at its height, appear regularly in scholarship and should be read as informed estimates rather than a census count. What's less disputed is the physical footprint: roughly four kilometres of fortified walls studded with dozens of towers, enclosing a built-up area far larger than most Roman provincial towns. That scale is precisely why Salona's archaeological park is the largest in Croatia today — you're not walking one monument, you're walking the outline of an entire city that once rivalled other major centres on the Adriatic.
The forum and the theatre
Like any self-respecting Roman capital, Salona had a proper civic core: a forum for public and political life, ringed by shops, temples and administrative buildings, and a theatre built around the same period, near the turn of the millennium. These weren't token gestures — a working theatre and forum meant Salona functioned as a full civic and cultural centre, not just a garrison or trading post. Little of either structure rises far above ground today, and both require some imagination to read against the open fields, but their presence at all tells you Salona had the population and the money to fund the same public life as any Roman city its size, anywhere in the empire.
The aqueduct's water source, still in use
Salona drew its water from a branch of an aqueduct fed by the spring of the River Jadro, a few kilometres inland — the same spring that, on a separate branch, supplied Diocletian's Palace once it was built six kilometres away. The Roman engineering choice proved remarkably durable: centuries later, after Salona itself was gone, Split's own water system was rebuilt to draw on that same Jadro spring, and a reconstructed version of the old aqueduct route served the city into the 20th century before modern waterworks eventually replaced it. The exact water source the Romans chose for their provincial capital, in other words, remains part of how the Split area gets its water — even though the ancient aqueduct itself was long ago superseded.
Why Salona mattered beyond Dalmatia
Salona's importance wasn't just local: as capital of Dalmatia it produced governors, hosted imperial business, and became closely tied to the emperor who is Salona's most famous native son — Diocletian, who restructured the Roman Empire's entire system of government during his reign. A man from a Dalmatian provincial capital ended up reorganising Rome itself, and when he retired in 305 AD he chose to build his palace just down the coast rather than return to Rome — a decision that only makes sense once you understand how significant Salona and its region already were within the empire. The capital's prestige is part of why Diocletian's Palace exists where it does.