Galerius Palace, Thessaloniki

The palace occupies the area of today’s Platia Navarinou and forms one component of a larger Roman monumental cluster that includes a hippodrome, the Arch of Galerius, and the emperor’s mausoleum known as the Rotunda. The surviving southeast quadrant of the original complex is laid out around a very large open court, and the masonry displays alternating horizontal bands of squared stone and brick, a mixed building technique common in late Roman construction.

At the heart of the remains stands a large octagonal hall, roughly 30 metres across. Its principal entrance faced south and each corner contained a recessed niche, with the niche opposite the entrance distinguished by its larger size. Within the octagon were spiral staircases that led to an upper floor; the central roof was almost certainly a dome that collapsed in the earthquake of 690 CE. The original floor was a mosaic that was later covered with decorative cut marble panels, and the interior walls were lined with marble and finished with capitals carved with the figures of Roman deities.

A south-facing vestibule attached to the octagon contains two apses: an apse is a semi-circular sanctuary end in architecture. This entrance area opens onto the principal courtyard, which measures about 47 by 88 metres and is oriented toward the ancient harbour. A carved fragment of an arch discovered in that courtyard bears two portrait cutouts, one of Galerius and one of Tyche, the personification of the city’s fortune; this fragment is displayed in the Archaeological Museum of Thessaloniki.

To the north of the octagonal core lies a rectangular building measuring approximately 30 by 40 metres. It contained eleven rooms and a peristyle, a columned courtyard, whose sides included four colonnaded aisles decorated with mosaics. Excavation showed that this block was occupied before the imperial palace was built, indicating earlier Hellenistic settlement and workshop activity on the same plot.

The palace complex also contained a suite of private baths served by an associated cistern and a large basilical hall; a basilica here refers to a large public hall used for administrative or ceremonial functions. The overall estate originally covered about 50,000 square metres, but today only the southeast sector survives, organized around the main courtyard and a network of mosaic-decorated corridors.

The decorative programme included extensive floor mosaics, with the atrium alone once covering roughly 68 by 8.5 metres, and wall-facing marble and carved capitals throughout interior spaces. Archaeological layers below the palace revealed two Hellenistic occupation phases and traces of an artisan quarter that likely related to the city’s first harbour, attesting to the long sequence of urban activity on the site. Restoration work on the surviving structures was carried out in the late twentieth and early twenty-first centuries, stabilizing and conserving the extant fabric for study and display.