The area between the two ports of Elaiussa Sebaste, located on a position overlooking the isthmus that linked the promontory to the mainland, was occupied continuously from the city's foundation to the moment of its abandon. The area was fortified between the IInd and the Ist century B.C. with the construction of an imposing polygonal wall and subsequently occupied by a series of buildings for the warehousing of merchandise. The monumentalising of this part of the promontory can be dated instead, to the imperial age when in the southern sector were built a wall in opus quadrata and along the northern port's front, a columned portico directly facing the sea. Around the Vth century A.D. pursuant to the re-organisation of the area's land-use, a grandiose architectural complex was erected in the promontory's western sector, to house the civil and military authority of the city. It is characterized by the presence of an ample circular portico, with two floors, that connected the two wings of the building which also included an apsed hall and a private chapel, both richly decorated.
In connection with its construction the greater part of the existing structures were obliterated or re-utilised: the columned road for example was partially closed off and transformed into the vestibule of the byzantine building. The palace was destroyed during the first half of the VI century A.D. and systematically spoliated. During the last phase of the city's life, which was definitively abandoned around the middle of the VIIth century A.D. the palace was partially transformed into a manufacturing facility.
The area of the Byzantine palace occupies the western side of Elaiussa Sebaste's promontory, in a location overlooking both the isthmus that linked it to the mainland and the two ports of the ancient city nowadays completely silted in. Its strategical position deterrmined its main functional characteristics: indeed, from the beginning its defensive function was related to the accessibility and vulnerability of this side of the promontory, to the port activities of the neighbouring two main harbours of the city and to its function as a link between the public quarter extending over the mainland and the promontory's residential quarters; for this reason the area was occupied continuously since the settlement's foundation probably during the late Hellenistic age until is final abandon during the middle of the VIIth century A.D. Many were the structural and functional modifications that took place among which it is possible to distinguish four principal phases that can be dated to the Hellenistic age (Ist century B.C.- beginning of the Ist century A.D.), to the first Roman age (1st century A.D.), to the Imperial age (end of the 1st to the beginning of the II nd century A.D. and finally to the Byzantine age (Vth-VIIth century A.D..
During the first phase, the promontory was fortified with the construction of a polygonal wall still partially visible today along the north-eastern and south-western sides of the site; Probably the area had an artisanal function due to its position on the edge of the dwellings and near the two ports, as demonstrated by the presence of a basin for the collection of water and rooms with kilns of the tandoor type. These latter already found during the prehistoric age, are dug into the floor level, had a cylindrical shape with vertical walls covered with clay and were used for the baking of bread and the cooking of meat; after having heated the ovens with braziers the food was spread directly on the walls and cooked by contact with the red-hot structure. However the scarcity of data in our possession does not allow to reconstruct in a systematic way the lay-out of the city during this phase.
The first Roman age is instead characterized by the presence in the north-western zone of the promontory, of warehouses for stocking food commodoties (horrea) the construction of which can be dated to the Flavian age (end of the Ist century A.D.). One of these structures, which was completely investigated and of which are saved today the outside walls, part of the partition walls and of the ceiling vaults, at a direct access from the sea as well as from the land and is constituted by a series of vaulted rooms, linked to each other with skylight windows for air circulation. A latrine still accessible today was connected to the horreum and was installed in one of the building's rooms; of the structure are still visible the floor paving and the channel coated with cocciopesto along two of the four sides. Its drainage pipe, which was found in the latrines' western wall, proves that the sewerage was directly spilled out into the sea.
While still keeping the same structural aspect, the horreum during the Trajan age (end of the Ist-beginning of the IInd century A.D.) went through some re-fitting that however maintained their same function until the Byzantine age transformation when the building's structures were re-used for the construction of a palace.
Between the end of the Ist and the end of the IInd century A.D. the area of the promontory was monumentalised by constructing a wall in opus quadrata and a columned portico along the northern port front of the city. The wall complex built more for a prestigious decorative effect rather than to answer real defensive requirements, involved however modifications to the lay-out of the structures in this area; the latrine for example was disposed of due to the presence of the big wall complex that closed off the drainage channel and was replaced by a new facility in one of the rooms southwards from the warehouse.
In general the area between the monumental front of the northern port and the horrea does not present architectural evidence that can be referred to this period because they were re-used or obliterated by the construction of the Byzantine palace. The latter constitutes the most significant phase of the promontory's area's transformation as it radically modified its structural plan and function. Between the end of the IVth and the beginning of the Vth centuries A.D. greater part of the city was transformed by the construction of real and proper wall fortification probably to be related to the Isaurian invasions.
As seat of the city's authority, the grandiose architectural complex was built towards the end of the Vth century A.D. in the vast area corresponding to the northern section of the promontory located between the two ports. The palace that was organized around a big circular two-storey portico that connected the various sectors of the building, was strongly influenced by the pre-existing structures yet modifying, however, their structural lay-out and functions; in the zone of the northern port, the columned street was closed off and the portico was transformed into the actual vestibule of the palace. The western sector of the great building included on the ground floor the imposing circular portico, an apsed hall and a series of minor rooms used as deposits, offices and service areas also leading to the other floors. The portico that was almost totally built on the rock bank, had an external colonnade made of 24 columns in proconnesian marble that left the central part of the building uncovered. The floor was paved most probably with lime-stone slabs.
From the vestibule it was possible to enter into the apsed north-western hall of the palace; the hall with a quadrangular plan (21,25 x 12,30 m,) was closed on one side by a semicircular apse that was not in axis with the building probably because of the pre-existing structures that strongly influenced its plan. In the upper level of the hall was situated the triclinium while in the room underneath a tribunal was identified, for the public and private audiences of the ruler. Particularly in the triclinium have been brought to light elements of its rich decoration such as columns with corinthian capitals, elements of opus sectile for the lining of the walls and sectilia pavimenta for its floor.
The southern sector of the palace presented on its first floor a columned portico that directly overlooked the port basin, founded on top of the horreum halls, the service rooms and the great cistern and a series of rooms that were for the private use of the ruler and his court. The rooms below instead, as already mentioned, re-used more ancient structures, and were used as warehouses and for activities dedicated to the daily life of the palace. In this southern sector , right against the rock cliff, is the second apsed hall of the complex which probably was entered from the portico and the rooms on the first floor; the decoration and in particular some elements pertinent to an iconostasis lead to believe that it was a chapel for private worship.
It seems evident that the palace, which is different from any other building of the same period from the point of views of its lay-out and especially decoration, must have played a role of primary importance during Elaiussa Sebaste's Byzantine life, as seat for the civil and military authority. The building however had a relatively short life; indeed it was destroyed around the '30s of the VIth century A.D. by a fire maybe to be related to the revolts during Justinian's age and subsequently spoliated in a systematic way.
In a later phase some parts of the palace complex, and more precisely the rooms previously occupied by the horreum were reused for artisanal activities. In the area next to the north port were indeed installed two kilns for the production of LR1 type amphora and some rooms were partially modified to cope with their new functions. In the first half of the VIIth century A.D. many collapses that took place in parts of the building and in the surrounding structures caused the definitive abandon of this area of the promontory.