Thera was a city-state, or polis, in the ancient Greek world. As with other city-states, it operated as an independent political and cultural entity. Located on the island of Santorini, Thera's strategic position in the southern Aegean enabled it to become a significant center of trade, maritime activity, and cultural exchange.

While relatively small compared to larger city-states like Athens or Sparta, Thera's governance and societal structure followed the typical polis model, which included political, religious, and economic functions centralized around its urban settlement. Its influence extended beyond the island, particularly during the period of colonization in the 7th century BCE, when Thera founded Cyrene in North Africa, demonstrating its role as an active and independent city-state within the Greek world.

circa 750 BCE- 400 CE

Early Settlement and Foundation (9th–8th century BCE)
Ancient Thera was first settled during the Geometric period by Dorian colonists led by King Theras, after whom the city is named. Positioned on the strategic Mesa Vouno ridge, the settlement capitalized on its defensible location and maritime connections, gradually developing into a regional hub for trade and culture.

Archaic and Classical Periods (7th–4th century BCE)
Thera flourished as a Dorian city-state, characterized by its civic structures, sanctuaries, and a well-organized society. The city maintained trade networks with the Cycladic islands, Crete, and mainland Greece, which is evident from imported pottery and inscriptions. However, its small population and limited resources constrained its political and military power compared to larger city-states.

Hellenistic Period (4th–1st century BCE)
Under the influence of the Ptolemaic Kingdom, Thera served as a key naval base due to its strategic location in the Aegean Sea. During this time, the city saw urban and architectural advancements, including the construction of monumental buildings, stoas, and sanctuaries, reflecting its increased regional importance.

Roman Period (1st century BCE–4th century CE)
Thera was incorporated into the Roman Empire and experienced a period of relative stability. While it lost its political independence, the city benefited from the Pax Romana, which facilitated trade and integration into the wider imperial economy. Renovations of public spaces and temples marked this era, blending Roman and Greek architectural styles.

Byzantine Period and Decline (4th century CE onward)
As Christianity spread, the city’s pagan temples were repurposed or abandoned. The Byzantine influence brought fortifications and the gradual shift of the population to more accessible lowland areas. By the early medieval period, Ancient Thera was largely deserted, marking the end of its historical prominence.

circa 750 BCE

Sanctuary of Aphrodite (Aphrodision)
The Sanctuary of Aphrodite, located on Mesa Vouno at an altitude of 396 meters, lies near the eastern coast of Santorini. Positioned about 50 meters northwest of the Byzantine city gate in the ancient town of Thera, this sacred site is dedicated to the worship of Aphrodite. The sanctuary consists of two interconnected structures, joined by a narrow gate with an opening 1.05 meters wide. The northern unit, oriented east-west, measures 7.25 by 2.87 meters, while the southern unit is a square measuring 3.50 meters on each side. The construction features limestone walls built on a schist foundation. Nearby, a large inscribed stone—unidentified but significant—suggests connections to the goddess.

Archaeological finds from the site reveal its historical importance. Over 100 clay vessels, both locally crafted and imported from regions like Attica, Corinth, and the Cyclades, were unearthed, alongside nearly 400 other objects. These include jewelry such as glass beads, bone pins, and bronze fibulae, as well as scarabs and small figurines. Among the figurines are a daedalic kourotrophos (a female figure holding a child), animal representations, and other human forms. Iron tools, loom weights, animal bones, and mollusks further illustrate the variety of artifacts linked to the sanctuary's activities. These offerings reflect the diverse cultural influences and the site's significance as a center for Aphrodite's worship.

Dating back to the late 8th century BCE, the sanctuary remained active through the Roman period, undergoing renovations in the 1st or 2nd century BCE. Initially thought to be a grave when discovered in 1900, later excavations and findings, including an inscribed 6th-century BCE cup and votive artifacts, confirmed its role as a sanctuary. Systematic excavations in the late 20th century by the Greek Archaeological Service provided deeper insights into the site's rich history and its enduring legacy as a place of devotion to Aphrodite.

circa 700 BCE

Agora
The Agora of Ancient Thera, situated on the eastern slopes of Mesa Vouno, was the central public and administrative hub of the city. Positioned at a prominent elevation, it offered breathtaking views of the surrounding Aegean landscape. This vital space served as a focal point for social, political, and economic activities in Thera, embodying the civic and cultural life of the ancient community. Architecturally, the Agora was framed by a series of structures, including stoas and administrative buildings, which provided shaded areas for gatherings and facilitated the city's administrative functions. Archaeological evidence indicates that the Agora was adorned with statues and inscriptions, reflecting its role as a center of both civic pride and cultural expression. Key religious structures, such as sanctuaries and altars, were also integrated into the Agora, underscoring the blend of public and sacred life typical of ancient Greek cities.

The Agora's layout and features evolved over time, accommodating changes in the city’s political and social landscape. From its foundation in the Archaic period to its continued use through the Hellenistic and Roman eras, the Agora of Thera remained a testament to the city’s enduring significance and its people's adaptability and ingenuity.

circa 323 BCE- 330 CE

Residential Quarter
The current remains of the residential structures in ancient Thera date back to the Hellenistic (circa 323 BCE until 140 BCE) and Roman periods (circa 140 BCE until 330 CE). The remains from earlier periods do not survive. The construction and development that ancient Thera experienced in the Ptolemaic period led to the expansion of the inhabited area of the city in the wind swept western part of the hill's upper ridge, while it appears that, until then, residences occupied only the relatively lower area around the agora. Besides, the Hellenistic house with the big peristyle open-air courtyard, around which the rest of the rooms developed, required a big area, in contrast to the small and simple houses of the Archaic and Classical periods. Dating from the Hellenistic and Roman periods, the residences appear to belong to mainly noble wealthy families and were often two-level with a big peristyle open -air courtyard.

circa 300 BCE

Sanctuary of the Egyptian Gods
During the Hellenistic times, a period of great receptivity to new gods and cults, the worship of eastern and Egyptian deities is spread across the Greek territory. In Thera, the Egyptian gods Serapis, Isis and Anubis become accepted in the early third century BCE and their cult is quickly integrated into the public and private religious life of the inhabitants of the island. The cult of the Egyptian triad of gods in Thera, which, in this period, belongs to the possessions of the Ptolemies, monarchs of the Hellenistic kingdom of Egypt, is closely associated with the presence and activity on the island of a large Ptolemaic garrison. A sanctuary in honour of the Egyptian gods is founded in the first half of the third century BCE. The sanctuary consisted of an unusual outdoor construction, that is a terrace, constructed mainly with artificial earth fill, the two sides of which were defined by the rocky land. Today survives mainly the rock-cut part of the sanctuary, with niches for votive offerings on one side and a bench for the placement of cult statues on the other. Two cisterns next to the sanctuary provided the necessary for the needs of worship "sacred water".

circa 280 BCE

Temple of Dionysus
North of the Agora stands a small Hellenistic temple of Doric order, dedicated to Dionysus. The façade and roof were marble, while the rest of the building was made of locally-mined stone. It dates from the third century BCE.

circa 275 BCE

Basilica Stoa
The imposing rectangular structure with the Doric order colonnade on the long axis that dominates the south agora served official and civic purposes and was undoubtedly the administrative center of the city. Its erection dates to the early third century BCE, however, in the course o ftime, the building underwent repairs. Two slabs of stone, which were built in to the wall directly opposite the entrance, refer to an extended repair that took place in the mid second century CE. On one of them is inscribed thepublic promise (eisaggelia) of the citizen T. Flavius Kleitosthenes Claudianus that he would take upon him the cost of repairing the building and on the other a resolution adopted by the assembly of the citizens (ekklesia demos) and the council (boule) in his honour for his benefactions offered to the city. During this repair, the north part of the building was transformed into a special area with a pedestal for the erection of statues, which appears to have been dedicated to the worship of the Roman emperor and his relatives. Moreover, the building was embellished with a rich sculpted decorations. According to the inscriptions, the so-called "Basilica Stoa" or "the stoa at the agora", was an old and distinguishable building, an ornament to the city.

A bust of a female marble statue, dating back to the first century BCE, was discovered in the Basilica Stoa during excavations. This bust is now displayed at the Archaeological Museum of Thera.

circa 250 BCE

Heroon of Artemidoros
Artemidorus’ Heroon is a modest yet intriguing rock-cut monument located on the northwest slope of Mesa Vouno in Santorini, along the path leading from Sellada to the ancient city of Thera. The structure features an almost semi-circular exedra with a radius of approximately 1.7 meters. A stone bench runs along its wall, surmounted by a vertically wrought rock surface transitioning into a vaulted ceiling. The focal point is a shallow niche carved into the bedrock, likely once housing a votive plaque. Below this niche, an inscribed epigram indicates that Artemidorus was heroized by the oracle at Delphi, providing insight into his elevated status and the heroon's probable function as a memorial.

The structure is modest compared to more elaborate hero shrines of the period, but its conspicuous placement high on the slope and along a prominent route underscores Artemidorus’ social standing. The lost votive plaque, likely of marble, might have offered further clues about his life and achievements. While the term "heroon" traditionally refers to shrines for divine heroes, its evolving usage in the Hellenistic period also encompassed funerary monuments for ordinary individuals. This ambiguity complicates the interpretation of Artemidorus’ Heroon, though the funerary context is supported by the epigram’s content and the broader historical understanding of hero cults.

The architectural simplicity of Artemidorus’ Heroon contrasts with the growing trend of extravagant funerary monuments in its era. Nonetheless, the structure's location and the epigraphic evidence highlight its significance, reflecting a blend of personal commemoration and public visibility that resonates with the cultural practices of Hellenistic Greece.

circa 250 BCE

Temenos of Artemidoros
The temenos was founded in the mid third century BCE. Its founder priest Artemidoros of Apollonios from Perge of Pamphylia, driven by a dream that he saw, settled in Thera during his old age. For the activity he developed, founding sancturies and embellishing the city, he was honoured twice with an olive wreath and was granted the right of citizenship of ancient Thera.

The open-air sanctuary was chiseled out of the rock by Artemidoros himself, altars, relief decorations and numerous inscriptions, mainly epigrams for the honoured gods and for Artemidoros, cover the front side fo the rick, whereas statues decorated the place. This is also where the resolutions of the demos of ancient Thera in honour of Artemidoros were placed.

Three steps with inscriptions in honour of Hecate and Pripos are carved, as well as the altars of the Dioskouroi, Omonoia and the gods of Samothrace, the eagle of Zeus Olympios, thelion of Apollo Stephanephoros, the throne of the goddess Tyche in the front, and the dolphin of Poseidon Pelagios. The set is completed by the portrait of Artemidoros depicted wearing a wreath, in the surrounding inscription he expresses his wish that his name remains immortal in eternity.

circa 100-200 CE

Exedrae
The exedrae, three buildings in the form of a temple, dated to the Roman period (circa first to second centuries CE), built in a line, housed statues of citizens that belonged to prominent families of Thera and were honoured by the city. Their construction remaisn witness their particularly careful architectural form. Built on a raised platform with three or four stapped courses, these formed a pedestal on the side opposite the entrance, where the statues were erected. On the southern exedra the bases of statues, belonging to Aristophanes of Eimertos and his step father Pantaxenos of Melehippos, with inscriptions have survived.

The middle exedra is assumed to have borne the inscribed slabs used forpedetal coating which mention Mnasikrita of Diodoros, priest of Dionysus, his wife Chairopoleia and her brother Tiberius Claudius Kyreina Medon. By the name of Chairopoleia became known, following the excavators' identification, which is nowadays questioned, a headless statue that L. Fauvel carried to France in 1788 CE. On the northern exedra also survive the inscribed statue bases, the honoured persons mentioned are Archis of Diodoros and most likely her daughter, Archis of Themistocles.

circa 250 BCE

Gymnasium of Ptolemaic Garrison
The building, constructed during the Hellenistic times, was considered by excavators to be a gymnasium, an exercise area, that is, for the Ptolemaic garrison. This assumption has been disputed and the few construction remains of the building -a large courtyard with statue pedestals and rooms on two of its sides- do not help to identify its use. However, as appears from the inscriptions and the numerous sculptures found in it, it is clear that it was an important public building, closely related to the garrison, which, during the Roman times, was a very popular place for the erection of honorary statues. Among the finds, an inscribed stele stands out (today found in the Archaeological Museum of Thera), which bears a letter of the king Ptolemy VI Philometor, of the year 164/3 BCE, to the commander of the garrison Apollonios of Koiranos, as well as a list of the donations of 213 officers and soldiers of the garrison, from 164/3 to 160/59 BCE, for the repair of a gymnasium. During the Byzantine times, roughly constructed houses were built in the area of the court.

circa 250 BCE

Ptolemaic Garrison Post
Thera, an important naval base in the Aegean Ptolemaic fleet, monarchs of the Hellenistic kingdom of Egypt, is organized, probably around the mid third century BCE, as one of their overseas possessions with the installation of a large garrison and Ptolemaic command. During the period of Ptolemaic domination, that is until 145 BCE, Thera is ruled by the commander of the garrison, who is appointed directly by the monarch. The building, to which a wide road leads, is identified as the seat of the commander and of several members of the garrison. The building is formed in two levels following the sloping ground. A portico with two columns, on the lower level, forms its imposing entrance. The portico gives access to the rooms of the ground floor and to a stepped corridor leading to the courtyard of the upper level. The courtyard, in the centre of which survive the traces of a water drain, is connected with a corridor, where rooms are opened in a row, probably dormitories; it is assumed that there were rooms on the other side of the corridor also, however today they have been destroyed.

circa 150 BCE

Theater
Built near the agora, in the densely structured center of the ancient city of Thera, the theater was also used according to epigraphic testimonies, as a bouleuterion. Despite its small size and its simple architectural form, it belonged to the most imposing buildings of the Hellenistic and later Roman period city. At its place a simpler construction most likely stood that was also used for assemblies. The theater appears to have been constructed in parts in the second century BCE. On its northern side, the only one with no adjoining buildings, there were two entrances, the one on the higher part towards the auditorium and the other towards the orchestra. Six stairways in the radial order divide the auditorium, which had the capacity of about 1,500 people, in five wedge-shaped seating sections. The senae building, with a stone proscenium, left the circular space of the orchestra free.

In the first century CE a Roman style scenae building with proscenium, decorated with statues of the imperial family, which occupied part of the orchestra, was built. Under the auditorium, a big cistern collected rain water. The oblongbuilding in the west of the theater was built at the same time with the auditorium, but still remains unknown wheather it was lined with the theater or not.

circa 100 CE

House of Tyche
The residential building, one of the latest in the ancient city of Thera, is considered to be a private house, although its position on the edge of the agora, where indeed it occupies part of its space, referes to a public building. Straight from the entrance was the side with the auxiliary areas and to the left the tetrastyle, typical of Roman houses, atrium; four columns supported the roof that left the space between them free; the rain water fell from the sloping roof, towards the hole, sides of the roof to the impluvium and finaly ended in to an underground cistern through a drain. The main areas of the residential complex were developed on the two sides of the atrium, while stairs on the south wall of the atrium led to an upper floor. THe use of the main areas of the ground floor, which formed on one side, with the exception of one area, a niche roofed with an arch, remains unknown; in front of one of those niches, fragments were discovered belonging to a statue of goddess Tyche (fortune), to whom the building owes its conventional name.

circa 600 CE

Agios Stefanos
The church, which survives today and is dedicated to Agios Stefanos (Saint Stephan), is built on the ruins of an Early Christian basilica, probably dated to the mid sixth century CE. The basilica was three-aisled, with a double narthex and an apse at its middle aisle. Along its northern side, there was an oblong adjacent structure with a small apse. After its destruction, probably due to an earthquake, the current church of Agios Stefanos with two vaulted aisles was built on its ruined middle aisle. Constructed with ancient architectural members, mainly from the basilica, the church is dated to the 8th or 9th centuries CE, when the inhabitants of Thera, as well as of the other islands, suffered from the invasions of Arabs and their constructions were rough and modest, contrary to those belonging to the Early Christian centuries. The two Christian monuments are eloquent witnesses of the inhabitation of the city even after the ancient times.