Diocletian's Palace (, ; ) is an ancient Roman palace and fortress complex in Split, Croatia. It was built at the end of the third century AD by the Roman Emperor Diocletian as his retirement residence. About half of the complex was for Diocletian's personal use, with the rest housing the military garrison. The complex was built on a peninsula southwest from Salona, the former capital of Dalmatia, one of the largest cities of the late empire with 60,000 people and the birthplace of Diocletian.
Today the palace forms about half of the old town of Split, with 3,000 inhabitants and numerous shops, boutiques, cafes, bars, and restaurants. In 1979, it was listed by UNESCO as a World Heritage Site.
History
Diocletian had ordered the construction of the heavily fortified compound near his hometown of Spalatum in preparation for his retirement on 1 May 305 AD. The site chosen was near Salona, the provincial administrative centre of Dalmatia, on the southern side of a short peninsula. Based on Roman map data (known through the medieval parchment copy of the Tabula Peutingeriana), there was already a Spalatum settlement in that bay, the remains and size of which have not yet been established.
thumb|left|Reconstruction of Diocletian's Palace in its original appearance upon completion in AD 305 (viewed from the south-west)
thumb|left|Diocletian's Palace in 2019 (viewed from the east)
The beginning of the construction of Diocletian's palace has not exactly been established. It is assumed to have begun around 295, after the introduction of the Tetrarchy (the rule of four). Yet ten years after that decision, when Diocletian abdicated in 305, the palace seems to have still been unfinished, and there are indications that some works were taking place while the emperor was residing at the Palace. It is unknown under whose architectural ideas the palace was built and who its builders were. The complex was modelled on Roman forts of the 3rd-century era, examples of which can be seen across the limes, such as the bridgehead fort of Castrum Divitia across the Rhine from Cologne.
However, the engraved Greek names Zotikos and Filotas, as well as many Greek characters, indicate that a number of builders were originally from the eastern part of the empire, i.e. Diocletian brought with him masters from the East. Still, a large part of the workforce was likely of local origin. The basic materials came from close proximity. The white limestone comes from Brač and some of Seget near Trogir; tufa was extracted from nearby riverbeds, and bricks were made in Spalatum and other workshops located nearby.
At Carnuntum, people begged Diocletian to return to the throne in order to resolve the conflicts that had arisen through Constantine's rise to power and Maxentius's usurpation. Diocletian famously replied:
This was a reference to the Emperor retiring to his palace to grow cabbages.
Diocletian lived on for four more years, spending his days in his palace gardens. He saw his tetrarchic system fail, torn by the selfish ambitions of his successors. He heard of Maximian's third claim to the throne, his forced suicide, and his damnatio memoriae. In his palace, statues and portraits of his former companion emperor were torn down and destroyed. Deep in despair and illness, Diocletian may have committed suicide. He died on 3 December 312.