The etymology of its name, Histria, seems to be connected with the ancient name of river Danube, Istros ( ̉Ίστρος ), according to information provided by Pseudo-Skymnos (Periegesis, 765). Danube had a different course when Histra was settled as a Milesian colony on the western shore of Pontos Euxeinos (Black Sea). One of its ancient channels, that no longer exists today, was flowing much closer to ancient Histria. Herodotus locates Danube's mouth close to the place where Histria was settled by colonists from Milet (Hist., II, 33). Also, according to Plinius the Elder, from Histria upwards (towards North), Danube's channels were flowing (Nat. Hist., IV, 11 (18), 41).

Histria was founded by Greek colonists from Milet, in the 7th century BC. The propitious location which provided a safe mooring place, a productive rural territory, the vicinity of river Istros, as well as an easy to defend promontory, determined a quite rapid social, cultural, economic development of the settlement. Before the raise of Tomis, in early Roman times, Histria was the main Greek colony on the Dobroudjan shore of the Black Sea. It already had a rich history extended on almost fourteen centuries of grandeur and decadence, when, in the 7th century AD it was abandoned by its inhabitants. Histria ceased to exist on the historical map of the region for more than twelve centuries, until it was discovered by Ernest Desjardins and excavated for the first time by Vasile Pârvan (in 1914).

There are several opinions regarding the exact date when the colony was founded. At first, the written sources didn't seem to agree upon the same date. Pseudo-Skymnos informs us about the contemporaneity between the foundation of Histria and the Scythian pursuit of the Cimmerians who were trying to get away from Bosforus. The last event was thought to have taken place at the end of the 7th century BC. More recent opinions place this event earlier, to the middle of the 7th century BC. This corresponds to the date provided by Eusebius from Caesarea, which is year 657 BC. Although this date has not been archaeologically confirmed yet, the earliest archaeological stratum being dated to approximately 630-620 BC, Eusebius' information seems to be correct. Only few parts of archaic Histria have been revealed, and the soil meant to level the terrain also contains early pottery shards, which seem to come from a smaller inhabited area that was settled nearby, earlier than 630/620 BC.

During its first six centuries of existence Histria developed as a typical Milesian colony. It had a defined pantheon, having Apollo Ietros as the main protecting god, as well as Zeus and Aphrodite. All of them were praised in temples built on the acropolis, which was protected by its own precinct wall, different from the fortified area of the civil settlement situated on the western plateau. The double precinct defense system was also used in the classic and Hellenistic periods. The administrative organization was typical for a Milesian colony. A chora was outlined, along with its villages, farms, sanctuaries, as well as a territory of influence, in order to control the neighboring areas with natural resources. This area of influence later became Regio Histriae. The main economic activities were agriculture, trade, as well as production of small amount of items, which were not meant for sea trade purpose, but for the local requirements of cheaper items. The first Histrian coins were issued in 475 BC. The main political events that also involved Histria in the Greek Period are related to: Darius’ expedition in 514-513 BC, Delian League, the conflict between Filip II and Ataias the Scythian ruler, the implementation of a democratic regime that replaced the histrian oligarchy, the rebellion of the west-pontic cities in 313 BC. During the wars of Mithridates VI Eupator, Rome showed her interest in ancient Dobroudja, especially in the city-ports, for the first time.

In the 1st century AD Histria was still under a powerful Hellenistic influence, which can be seen in the cultural and religious tradition, urban features, especially the use of the Hellenistic precinct and its street network. Although during the reign of Hadrian a new precinct was built, expanding the fortified area towards west, the eastern part of the city still preserved its Hellenistic characteristics. During the Early Roman period (1st-3rd centuries AD) Histria was a flourishing city-port, with an articulated street network and impressive buildings. Although we don't have enough archaeological data for this period, the epigraphic material fills this gap. In several inscriptions dated to the second decade of the 3rd century AD Histria bears the epithet λαμπροτάτη πόλις. Only an important city with a certain degree of economical, social, cultural and political development would have been entitled to use such an appellative.

The Late Roman - Early Byzantine period was quite a hectic one for the newly established province of Scythia Minor. Moments of peace and prosperity alternated with military conflicts, caused by barbarians, situated outside the empire's borders. Temporary solutions like the Naissus victory, restitutio imperii that followed, Diocletian's reforms, etc, were too evanescent to provide a long lasting peace and the necessary equilibrium for a continuous development for cities situated in the limes provinces. All these events influenced Histria's historical trajectory. Its fortified territory decreased to almost one third of the early one. What was once one of the most important cities of Moesia Inferior is now depicted as "once, a very powerful fortress" (Ammianus Marcelinus, Rerum gestarum libri XXXI, XXII, 8, 43). Though smaller than the early city, Histria had an organized urban area, with a street network, slightly different from the early one, modified to fit the new precinct and its gates, also residential districts, with large villae, public places, a district where luxury products were sold, an economical district, an official district etc. One of the most important features of late Histria is the establishment of an episcopium during the reign of emperor Anastasius. The bishopric basilica was built during the reign of emperor Justinian, in the center of the late fortress.

In time, the sea level raised and flooded the plain situated north-west from Histria, covering some tumuli, as well as the roads that were heading towards the northern part of Scythia Minor. At the beginning of the 7th century AD Histria ceased to exist as an urban center. Scattered proof of life between its ruins was found. The latest dwellings are dated to the 11th and 13th-14th centuries. Only three such dwellings have been found so far.

The Late Roman fortification built its urban structures upon the earlier ones, ranging them along the earlier main streets, which continued to function, with rather small modifications and improvements. There were also early monuments that were kept inside the fortified area, without being dismantled, and that were later reconstructed and improved. For instance a bath complex (generically called Thermae I) situated in the south-western part of the city, built in the 1st century AD, continued to function, with several restoration works and even with a different utility. The main gate of the city opens towards a large plaza (25x14.50 m). There visitors can see a civil basilica, built in the 3rd century AD, considered to have been one of the administrative buildings of the city, along with other two - , situated on the eastern side of the alley that relates the plaza to Thermae I. Towards east, a paleochristian basilica (5th-6th centuries AD) can be seen. The official district of the city, situated south from the main gate, includes a rectangular basilica dated to the second half of the 3rd century AD (reconstructed in the 4th century AD), a commercial building (tabernae), where luxury products were sold (4th century AD), another plaza, surrounded by columns (4th century AD), etc. All these buildings, dated mostly to the 4th century AD, were overlapped by late constructions. Unfortunately not much can be said about these buildings because they were removed between 1921 and 1942.

The most important building of late Roman Histria is the bishopric basilica situated in the central part of the city (5th century AD).

Entering the fort through the narrow gate, situated in the southern part of the western wall, one can also see the economical district, on the right side, as well as another basilica, at the end of the street.

One of the residential areas is situated east from the bishopric basilica. Four large villae, having a similar typology were discovered there.

In 1914, the Romanian archaeologist, Vasile Pârvan carried out the first excavations at Histria. The Late Roman city wall was the first monument discovered. Since then, several generations of Romanian archaeologists revealed large surfaces of the Late fort, as well as almost the entire line of its defense wall (where it was still preserved), which protected the city from the second half of the 3rd century AD until the beginning of the 7th century AD. It closed an almost 7 ha large surface, three times smaller than the area protected by the previous precinct, the Early Roman one. Its first phase (phase A - second half of the 3rd century – end of the 3rd century AD) overlaps segments of the Hellenistic precinct, using its foundation to achieve a greater stability. Another interesting particularity of phase A is the use of columns to build a durable groundwork (worn material from earlier constructions which were dismantled). It was provided with three gates, and three, maybe five towers. It was destroyed during the Gothic attack, at the end of the 3rd century AD. During the reigns of Diocletian and Constantine the Great, phase B was erected, integrating a larger territory towards north and south. It had a more complex defense system provided with seven towers on its western side and three corner towers (south-east, north-west and north-east). The eastern wall of the Late fortification, not entirely preserved, was not provided with towers. Through the main gate, 3.30 m large, and the western gate, 2.40 m large, vehicles could also pass. In its last phases several restoration works were undertaken (at the end of the 4th century AD; during emperor Anastasius' reign and at the end of the 6th century AD), and in the last decades of Byzantine Histria, only the western wall was still functional. The main gate, protected by rectangular towers on each side, was used during all five phases.

Harbor: Histria was provided with a natural docking place since its early years. Although there were no harbor installations at the beginning, massive imports from several maritime centers of the Greek world, show that the natural bay was more than enough to shelter an intensive maritime trade at Histria. The existence of Histria’s harbor is a certain fact, as the imported artifacts, coins, epigraphic material and ancient written sources prove. Even if no archaeological evidence was found so far, there are two possible locations of the place where harbor installations could have been set. Histria’s ancient harbor could have been located at the city’s northern limit, where what used to be a large plane is now flooded. Against this possibility stand the general morphological aspect of the western coast of the Black Sea and the climatic aspects that, according to Vitruvius’ recommendations, could not have allowed the setting of a harbor opened towards north. It is true that this was taken as a general rule by the cities situated on the western shore of the Black Sea, but there were also exceptions. Mesembria for instance had two harbors, during the roman-byzantine period, and one of them was situated in the northern bay of the Mesembrian peninsula.

The southern part of the fortification, were used to exist a bay, now silted, is another possible location for Histria’s roman-byzantine harbor. Its hypothetic status has now a certain amount of certainty, mainly because of the new archaeological research, carried in this part of the ancient city. The archaeological research provided important reasons to locate the harbor (or at least one of the docking places) in here. Several stone platforms were discovered in these past years (2010, 2011). They have been interpreted as evidence of installations of the late phase of Histria’s harbor. The harbor was probably guarded by a light-tower, as representations on coins suggest.

Today Histria is a large archaeological reservation. Its territory along with its necropolises reaches approximately 75 ha. The most important Romanian archaeological site situated on the western coast of the Black Sea, Histria has a history of almost 100 years of assiduously archaeological research. This made Histria one of the first schools of archaeology for many generations of students from all the important traditional Romanian universities (University of Bucharest, "Alexandru Ioan Cuza" University from Iași, "Babeș Bolyai" University from Cluj etc.). Therefore, besides the archaeological site, there are also few small buildings for accommodating archaeologists and students, as well as deposits for a proper preservation of the excavated artifacts. As Histria is a cultural attraction for Romanian and especially foreign tourists, a new museum had to be built in the 80's. As a result, nowadays Histria consists of an open air museum (the site itself), an indoors exhibition place, an accommodation area (only for archaeologists and the museum staff), deposits, a restaurant and a parking lot.