The history of Dacia comprises the events surrounding the historical region roughly corresponding to the present territory of Romania and Moldova and inhabited by the Getae and Dacian peoples, with its capital Sarmizegetusa Regia.

After clashing first with the Macedonians (4th century BC) and then with the Thracians (3rd century BC), in the 1st century BC the Dacians succeeded in establishing, under King Burebista, a stable autonomous kingdom. Upon the death of the great ruler, however, his kingdom dissolved; a fluid situation ensued, with numerous clashes with the Roman Empire, which had meanwhile reached the southern borders of Dacia. In 101 AD, Emperor Trajan launched a campaign to conquer the area, which ended in 106 with the death of King Decebalus and the establishment of a new province (see Roman Dacia). However, Roman rule already came to an end in the 3rd century, when the limes was returned to the Danube. Later invaded by Goths, Slavs, and other nomadic peoples, with the transition from Antiquity to the Middle Ages Dacia ceased to be understood as a unitary region and its territory was broken up between Transylvania, Wallachia, Moldova and Bessarabia.

First political entities in the region (6th to 2nd centuries BC)

It is to Herodotus that the first indications of the indigenous population of Dacia are due. In fact, he described the population of the Getae of Dobruja, who in 514 BC clashed against the armies of Darius I of Persia.

In 334 BC, the Getae were attacked and soundly beaten by the Macedonian armies of Alexander the Great, for they had allied themselves with the neighboring Triballi, who in previous years had carried out several raids against the Macedonia of Philip, father of the great Macedonian leader. Alexander passed Mount Hemo, pursued them and forced the Triballi into battle near the mouth of the Lyginus River near the Danube. Once beaten, their king, Sirmus, found refuge on the island along the Danube, of Peuce (now Peuke). The Macedonian leader, determined to give these peoples a show of strength, ferried across the Danube river, moved with his armies into Oltenia, and, clashing against an army of 10,000 infantrymen and 4,000 Getae horsemen, succeeded in beating them and subduing these peoples inhabiting ancient Dacia.Plutarch, Parallel Lives, Alexander the Great, 11.

In 326 BC, the fortunes were reversed, and this time the Getae succeeded in beating the Macedonian armies, commanded by the general named Zopyrion, on the Gotic steppe south of Bessarabia. The Macedonian general, while returning from the failed siege of the city Olbia on the Black Sea, met his death along with an army of as many as 30,000 soldiers.Emile Condurachi e Constantin Daicoviciu, Archeologia Mundi: Romania, Roma 1975, pp. 98–99. The Getae had thus succeeded, eight years later, in avenging their previous defeat.

Around 300 BC, the new king of the Thracians, Lysimachus (306-281 BC), decided to invade and annex the Getaean territories of Wallachia north of the Danube. He entrusted his armies to his son Agathocles, who, however, was beaten and taken prisoner by the Getaean king Dromichaites, who was eventually persuaded to let the Thracian king's son go free in the hope that relations between the two peoples would improve. Lysimachus, in spite of the geta king's soothing gesture decided, on the contrary, to invade the enemy country again, meeting with fresh failure. The Thracian king, in fact, was again defeated and taken prisoner, and only thanks to the indulgence of the king of the Getae was he allowed to live and set free. The Getae, however, this time succeeded in obtaining advantageous terms in the newly concluded peace treaty, achieving a solid bond between the two peoples, thanks in part to the marriage between Dromichaites and Lysimachus' daughter.Strabo, Geographica, VII, 3, 8; VII, 3, 13.

During the 3rd-2nd century BC, news becomes scarcer. However, a few conflicts between the kings of the Getae and the Greek colony of Histria on the Black Sea (south of the mouth of the Danube river) are known, where the latter paid the consequences of the clash so severely that it was forced to pay regular tribute to the kings of the Getae (episodes in 250 BC and 180 BCEmile Condurachi e Constantin Daicoviciu, Archeologia Mundi: Romania, Roma 1975, pp. 99–100.). And again in 168 BC, Perseus of Macedon attempted to hire as many as 10,000 foot soldiers and as many horsemen from among the Getae. However, the exaggerated cost demanded by the Transdanubian mercenaries, a total of 150,000 gold pieces, deprived the Macedonian king's army of a sizable allied force that was crucial to the impending clash with the Romans near Pydna.Appian, Macedonian Affairs, XIX.

Literary sources begin to mention the Dacians, as a population inhabiting, from the beginning of the second century BC, the interior of the Carpathian mountain arc. In fact, Pompeius Trogus tells of the conflict that led the then Dacian king, Oroles, to beat back and repel an incursion of Bastarnae Germans, who had attempted to penetrate from the east, into the fertile plains of the middle reaches of the Mureș river.Pompeius Trogus, Historiae Philippicae. A new conflict with the Bastarnae occurred in 112-109 BC, but again they were repulsed, failing to weaken the power of the Dacians, which on the contrary increased, so much so that it is precisely at this time that we can discern the shift of the Daco-Getic power center from the plains of Wallachia to the heart of Transylvania.

The kingdom of Dacia in the first century BC: Burebista and the Romans

It was with the beginning of the new century that the Romans, busy fighting Scordisci and Dardanians, came to clash with their allies as well: the Dacians. Indeed, Florus recounts that in 74 BC,AAVV, I Daci: mostra della civiltà daco-getica in epoca classica, Roma dicembre 1979-gennaio 1980, p.31. the governor of Macedonia, Gaius Scribonius Curio, after defeating the Dardanians (for whose victory he deserved a triumph), "came as far as Dacia, but retreated frightened before the thick shadows of its forests."Florus, Epitome of Roman History, I, 39, 6. He was perhaps the first among Roman generals to penetrate Dacia once he crossed the Danube.

In the first half of the first century BC, a state arose on the territory of ancient Dacia, the main center of which was located in the southern Carpathians of Transylvania, in the area of the Orăștie massif, coming to encompass at the time of its greatest expansion the entire Dacian-Getic lineage. The formation of this early Dacian state was enhanced especially under the enlightened leadership of King Burebista, a contemporary of Gaius Julius Caesar, who restructured the internal order, completely reorganized the army (which Strabo reports could field as many as 200,000 armed menStrabo, Geographica, VII, 3, 13.), so much so as to raise the morale of these people, and expanded the limits of the kingdom to their highest peak.

This progress led to a significant demographic increase in the Dacian population, so much so that the number of settlements grew with great rapidity, and a number of new settlements sprang up during this period: from Popești to Cetățeni, Piatra Neamț, Pecica, Piatra Craivii, Capilna, Costești, and on to Tilișca. Of these newly established settlements, Costești, Piatra Craivii, and Capilna were fortified and located right in the center of the new state of Burebista. Other older sites, such as Răcătău and Slimnic expanded their area and population wealth, thanks to recent archaeological finds of various utensils.Hadrian Daicoviciu, Lo stato dacico, in I Daci: mostra della civiltà daco-getica in epoca classica, Roma dicembre 1979-gennaio 1980, p. 29.

Underlying this development was certainly the progress in ironworking, but also the use of squared stone as a building material, agricultural progress (with iron plowshares for plows), mining (gold and silver in particular), carpentry (with the clearing of areas near settlements), and pottery (for which the potter's wheel was introduced). Along with the development of the productive forces of the new Dacian state, trade with neighboring countries also intensified, in particular numerous finely crafted Hellenistic-style objects were imported from the nearby Greek colonies on the Black Sea, such as vases, metal mirrors, bronze objects, amphorae, etc., and the minting of geto-dacian-style coins intensified (between 200 and 80 BC).

Burebista, after reorganizing the state internally, reformed the army, creating a complex and solid system of fortifications in the Orăștie Mountains, around the capital, Sarmizegetusa Regia, and the center of the new state. In addition, the population increase and increased military strength led to a whole series of campaigns conducted in the years c. 60-48 BC:

in 61-60 BC, the Dacian king turned toward Illyria and subdued the Scordisci people of the lower Sava river valley.

in 60-59 BC he subdued the entire Tisza river plain, taking his armies as far as Lake Balaton in present-day Hungary, and perhaps as far as the Morava river, subduing the territories of Pannonia and putting the Celtic peoples of the Boii and Taurisci on the run.Strabo, Geographica, VII, 3, 11. The result was that in 58 BC the Boii, who fled after the defeat, joined the migration of the Helvetians westward, which Gaius Julius Caesar succeeded in blocking in Gaul, while the Taurisci were forced to migrate to Noricum.Caesar, De bello Gallico, I 5:2-5. The Boii had been forced to migrate westward by the devastating force of Burebista's Dacians, who had driven them from their territories west of Lake Balaton. Some had taken refuge in Bohemia, others had poured into Noricum, besieging and conquering the ancient city of Noreia, and finally others had traveled down the Danube River to the territory of the Helvetians, whom they joined.

around 55 BC he turned his armies eastward and after repeatedly defeating the Bastarnae Germans, he succeeded in occupying the Greek colonies on the coast of Pontus Euxinus, starting with Olbia on the Bug river, then fell Tyras on the Dniester river, later Histria (in Dobruja), Tomi, Odessos, Mesembria and Apollonia.

around the years 50-48 BC Burebista expanded his conquests to the foothills of the Balkan Mountains.Hadrian Daicoviciu, Lo stato dacico, in I Daci: mostra della civiltà daco-getica in epoca classica, Roma dicembre 1979-gennaio 1980, pp. 30–31

It is said that during the civil war between Caesar and Pompey, he attempted to take advantage of the situation by sending ambassadors to Pompey, to whom he would promise his military aid, in return probably for recognition of his conquests along the right bank of the Danube. However, before he could officially ally himself with the latter, Caesar succeeded in defeating Pompey at Pharsalus in 48 BC, thwarting any possible alliance of the Dacian king. On the contrary, it highlighted how dangerous the new kingdom formed in Transylvania could be for Rome.

The Dacians, in fact, after the successes of the last decade, appeared so formidable in the eyes of the Romans that Caesar himself had planned an expedition against themSuetonius, The Twelve Caesars, Caesar, 44. (perhaps also in revenge for the discourtesy suffered during the Civil War), which did not, however, take place because of the death of the Roman dictator on the Ides of March in 44 BC.