Roman emperors aren’t renowned for their modesty, but Diocletian had an ego apart. Preferring the title Lord and God, to the usual First Citizen, he ordered a retirement home so massive a whole city was built around it. In AD305, after 21 years of service to the Roman Empire, he left to grow cabbages on the Dalmatian coastline, and Aspalathos was founded.

Now known as Split, Croatia’s second city after Zagreb is often overlooked en route to the islands, but with rowdy markets, stunning ancient architecture, secretive cobbled streets and a constantly lively stretch of bars by the seafront, it’s worth much more than a cup of coffee while you wait for a ferry.

The Diocletian palace, considered the greatest Roman ruin in western Europe, is the headline attraction. While its construction began half way through the Emperor’s reign, the intended abode was so fancy, the pressure was on to meet the deadline. The builders rose to the challenge, shipping in materials from Egypt and Greece to fill out the 170m by 190m floor plan, which even included its own barracks. After Diocletian died in AD313, the palace became a holiday home and then a makeshift fortress. Today, with its crumbling walls woven into the fabric of the city, Diocletian’s Palace wouldn’t protect you from much, except the heat of the midday sun and the street-level crowds.

Wander into a cool maze of the palace’s underground chambers where the only sound is the murmur of other visitors and faint whispers of music from the shopping arcades above (a warbling Unchained Melody in my case). Once filled with sewage, these rooms were the foundations for the royal quarters, the remains of which you’ll find upstairs on the Peristyle, an open-air square flanked with colonnades. The black granite sphinx here was one of 10 imported from Egypt and a potent reminder of the palace’s former grandeur.

Dotted around the edges of the square are bars and restaurants where you can linger until the early hours watching bats swoop around the nearby campinale. By day, climb the bell tower, which belongs to the Cathedral of St Domnius (once Diocletian’s mausoleum). It’s a vertiginous trek, and one to be done off the hour to avoid the bells, but the view is superb. To the north, market stalls stretch out below the Dinaric Alps, and to the south, the red-tiled houses stop abruptly at the sparkling Adriatic Sea.

With such obvious compass points, it’s almost impossible to get lost in Split. Despite the dark, labyrinthine alleyways filled with cafés, restaurants and artsy boutiques, eventually you break out into one of the city’s many squares. From here, with sea or mountain range in the distance, you can get your bearings. Narodni Trg (People’s Square) is the main piazza, covered with white marble so shiny you can almost see your face in it. Like the Peristyle, it’s almost impossible to walk from one side to the other without being tempted by an al-fresco Kaltenberg.

Nearby is Split’s fish market, a mass of glistening scales and hollering vendors, as you’d expect. The main difference from other fish markets of the world is that there are no flies, thanks to the sulphurous spring that runs beneath the city (also responsible for the strange tang to the air).

Supermarkets are yet to hit Split which means most grocery shopping is done at Pazar, a huge marketplace where stalls creak under the weight of fruit and vegetables. While tributary markets sell other goods like clothes and chocolate, they’re rivalled by shops at the sea front. Here, international chains, from Hugo Boss to Topshop, have followed the holidaying tourists.
The accommodation remains simple. Aside from a smattering of hotels and hostels, there are sobas – rooms for rent in private houses. Ours was comfortable, decently priced and unpretentious – we shared the family bathroom. As well as being a good way to get to know the Splicani, you could find yourself living with a relative of Goran Ivanisevic, who was born here and is now a more permanent fixture in the city after leaving the pro tour at this year’s Wimbledon, it seems Split is the retirement home of choice among past emperors. If you’re on your way to the islands, make like Goran and Diocletian and rest up at this enchanting port, at least for a few days.

Visit TNT’s Croatia Travel Guide.