At the end of the Aeneolithic Age, around 3500 BC, an important ethnic and cultural synthesis took place that led to the appearance of new peoples and cultures in Central Europe and the Balkans. These peoples can be identified with the traditional ethnic groups of Old Europe: the Hellenes, the Illyrioi, and the Thraikes. The Thraikes came to inhabit the vast territory from the south of Poland, to the north of Hellas and from Slovakia to north-western Anatolia. The Hellenic historians related that "The population of Thraike is greater than that of any other country in the world except India. If the Thraikes could be united under a single ruler in a homogenous whole, they would be the most powerful nation on earth and no one could cope with them."

The next historical period, the Bronze Age ( 3500 to 1200 BC) also includes the development of the Thraikes. A spectacular demographic growth occurred, as proven by archeological discoveries of many large settlements, some of them fortified. The metallurgy practiced in Bronze Age Getia, although not of local region, attained high levels as evidenced by the rich deposits of bronze items found in parts of Transylvania. Along the tribal aristocracy, a class of priests may have also existed.Their rituals ware preformed in sanctuaries. The lower classes engaged in mining, metallurgy, handicrafts,agriculture and commercial activities.

Beginning in 1400 BC, important ethnic and cultural developments took place in the Carpathian-Danubian territory. Nomadic tribes from the Sabatinovka culture moved towards the west while the creators of the mound tomb culture (hugelgraber-kultur) came from the regions of central Europe toward the east and southeast, causing the dislocation of some Thracian tribes and the massive movement of peoples toward southeastern Europe, to north-eastern Anatolia and beyond to Aigyptos, Phoinikia, Syria, and Palestine. Being in contact with advanced civilisations such as those of the Hellenes, Persai and Makedones the southern tribes of the Thraikes experienced a more rapid development, while those living north, including the Getai, had a slower development, due in part to the continuing invasion of nomadic tribes.

As Strabo records: "the Getai are those who occupy the territory toward the sea and the east, while the Dakoi are those who live in the opposite part toward Germania and the source of the Donaris." Despite this they spoke the same language and belonged to the same ethnical group. The last phase of the first Iron Age (650 to the latter half of the fifth century BC) and the first two phases of the second Iron Age (the latter half of the fifth century BC to the beginning of the second century BC) denote a distinct historical period in the evolution of these northern Thraikes. They were still divided, passing through stages of political development that differed from region to region. They were greatly influenced by the people with whom they came in contact.

One such people, the Hellenes, founded in the mid-seventh century BC several colonies (apoikia) and commercial settlements (emporia) such as Histria on the shore of Lake Sinoe, Tomis (today Constanta), Argamon, Kallatis (today Mangalia), and Tyras (today Cetatea Alba), on the western and northern shores of the Black Sea. These settlements belonging to the "Hellenes beyond the seas" played a vital role in the development of the Getai and Skythai due to their multiple economic contacts, political relationships, cultural developments, and economic exchanges with the local communities. Close relationships formed between the Getai and Hellenes that led to the gradual Hellenization of the native tribes. Hellenic ceramic goods, luxury items, and superior oils and wines spread throughout Dobrogea and beyond to Moldavia, Muntenia, and Oltenia. Rapid cultural progress took place. Some tribes, including the Getai, founded powerful political organizations led by dynasts during the sixth to the third centuries BC. Herodotos relates in his "Histories" that during the expedition led by the Persai King Dareios I against the Skythai north of the Black Sea, in the year 513 the Getai resisted the advance of the Persian Army, but were enslaved though they "were the most manly and law-abiding of the tribes of the Thraikes." Later, Thoukydides speaks of the same Getai fighting alongside the Odrysian King Sitalkes adgainst the allies of Athenai in the Peloponesian War of 429 BC.

Philippos II of Makedonia, in order to punish the Skythai king Ateas for his treachery, concluded an alliance with the Getic King Kothelas. This alliance was consecrated by the marriage of Kothelas's daughter Meda to Philippos in 339 BC. The Getai and Makedones drove the Skythai from Kallatis and Kothelas became the master of the Black Sea colonies. Philippos's son, Megas Alexandros, undertook an expedition against the Triballoi in the year 335 BC, in preparation for his great Persian campaign. The legendary general defeated the Triballoi and made a brief expedition north of the Istros (Danube) against the Getai who mustered an army of 4,000 horseman and 10,000 infantry. The peace was short-lived, however, as around 325 BC the military governor of Thraike was killed together with his entire army by a Getic-Skythian combined force.

This victory, combined with the death of Megas Alexandros in 323 BC, weakened Makedonian control in the region and allowed the Getai to become the dominant political factor in the region. The tribes offered vital assistance to the Hellenic colonies on the Black Sea coast, led by Kallatis in their struggle against the Makedonian Lysimachos, the King of Thraike. But the most important episode, related by several ancient authors (Diodoros Sikilios, Strabo, and Trogus Pompeius) was the conflict between Lysimachos and the Getian kingdom of Dromichaites. The kingdom of Dromichaites was located in Eastern Muntenia, having its capital at Helis (Piscul Crasanii). The Makedonian king tried to make Donaris his northern frontier, while the Getian tried to mentain his control over the colonies on the Black Sea coast. Lysimachos organized two campaigns north of the Istros, in 300 and 292 BC. The result was a military disaster as both Lysimachos and his heir Agathokles ware captured. The Makedones finally recognized Getic supremacy over the lower Istros and Black Sea. A royal marriage concluded the alliance between the two powers. Two Getic rulers (Zalmodegikos and later Rhemaxos) continued to exercise control of Histria. Around the year 200 BC King Oroles from southern Moldavia opposed the advance of the Bastarnai. Another king, Rubobostes, ended the Celtic domination in Transylvania. The Getai aquired significant political experience and this allowed them to become the most advanced "barbaroi" in the centuries to come as they made the transition from tribal society to a state society.

By the middle of the second century BC the Geto-Dacians entered a new period of development, the most advanced in their entire history. The most interesting part of this period is the apppereance of proto-urban settlements known as davas. They were organized areas, being political, commercial, religious and military centers of the dacian tribes. Some used Roman, Celtic or Hellenic techniques known as Murus Dacicus. The Dacian fortresses found north of the Danube, like the complex of fortifications in the Sebes mountaines, formed the strongest defensive systems in the "barbarian" world. The Getian craftsmen had ties with the Roman and Hellenic worlds, which brought an unprecedented level of economic development. The Dacian goldsmiths even exported to far-off Scandinavia. The society becomes clearly divided into two social groups: the cometai (the free people) and tarabostes (the nobility). The leaders of state were elected from the nobility, which was distinguishable by the fur caps. A class of priests developed to serve as intermediaries between god and man. This was part of the transition to the cult of Zalmoxis, which became fully incorporated into the state structure. Like noblemen, priests wore fur caps to express their position. The high priest was an important position second only to the king. It was this cult that allowed the unification of the Getian tribes to occur.

During the first century BC they were finally united under the rule of King Burebista (70-44 BC). As his power increased, he opposed Roman supremacy north of the Balkans. He is referred to by the people of Dionysopolis as "the first and the most powerful among the kings who ever reigned in Thraike, master of the entire region this side of the great river." His kingdom centered at Arcidava gradually expanded in all directions. Getian armies crushed the Boioi and Tauriskoi in the winter campaign of 60 BC. He later (in 55 BC) conquered the Hellenic colonies on the Black Sea coast, defeating the Bastarnai and securing the shoreline from Olbia in the north to Apollonia in the south. Now Getia was a force to be reckoned with. Previous military succeses inspired the Getai to mount a campaign south of the Istros around 48 BC. The result of this was contact between the Roman and Getian worlds. Burebista could afford to interfere in the Roman civil war by supporting Pompey in his struggle against Julius Caesar. Thus, the Getians were now united against a common foe. When the threat of an invasion ended with the death of Caesar on the Ides of March in 44 BC, the sense of national unity collapsed, as the tarabostes assassinated Burebista. His succesor, the high priest Deceneus, failed to keep the tribes in line. In the following decades four minor kingdoms emerged from the civil war and none of them was individually strong enough to halt the Roman advance in the Balkans.

A capable strategist, diplomat and politician, King Decebalus united the Getians once more under his rule (87-106 AD). He introduced a centralized administrative system, which led to the development of the most well-organized barbarian states in the first century AD. The fledgeling Dacian state became a menace to Roman authority as Decebal mobilized the tribes in a raid against the Roman garrisons of Moesia Inferior in 87 AD. Oppius Sabinus, the Roman governor, along with his entire legion, were slain. He later repelled the Roman counter-offensive led by Cornelius Fuscus, capturing the Roman eagle. The line of victories ended at Tapae, where the Roman army of Tetitus Iulianus finally defeated the raiders. The Roman Emperor Domitian was forced however to conclude a peace treaty with the Dacians in 89 AD. Dacia became a client kingdom and received Roman war machines, engineers and even financial assistance to improve the Dacian fortresses. When Marcus Ulpius Traianus became emperour in 98 AD, he decided to eliminate the Dacian kingdom. Apart from desire for vengeance, the new ruler needed to secure his flank along the Istros and gain the rich gold mines of the Apuseni mountains.

The result was a series of Dacio-Roman wars (AD 101-102, 105-106), at the end of which Dacia would become a Roman province, bringing about the end of Zalmoxianism. The emperor's 150,000 men from Illyria and Moesia crossed a bridge of boats at Berzovia. The Getai suffered a crushing defeat at Tapae. Only the break of winter halted the Romans from reaching the Getian capital of Sarmisegetuza. In the spring the Dacians aided by Roxolani Sauromatai went on the offensive to relieve their capital. They failed as the Romans defeated them at Tropaeum Traiani and Nicopolis. Decebalus sued for peace. The peace terms ware so humiliating for the Dacians that a new conflict was inevitable. Three years later the conflict broke out as Decebal refused to dismantle his fortresses. Marching his troops on the bridge across the Danube, Trajan reached the walls of Sarmisegetuza a second time. The capital fell to the Romans and Decebalus was forced to retreat north. Pursued by Roman cavalry the king chose to commit suicide, rather than fall prisoner. Getia was no more; Rome became the sole authority in the Carpatho-Danubian region. Their colonists later merged with the shattered tribes to form the Romanian people of today.