Aquileia was an ancient town in northeastern Italy, located near the head of the Adriatic Sea. Founded in 181 BC as a Roman military colony, it was originally established to secure the eastern borders of Italy against neighboring tribes such as the Carni and Histri. The city subsequently grew into an important frontier military city. Its strategic location made it an hub for trade and military operations, particularly for Roman expansion toward the Danube. In classical antiquity, Aquileia was a major Roman city with an estimated population close to 100,000 in the 2nd century AD.

Aquileia was one of the first cities in which Christianity could be practised unhindered; the Patriarch of Aquileia was the second most important person of the Western Church after the bishop of Rome.Hermagoras in Ökumenisches Heiligenlexikon. In the 4th century, the construction of the Patriarchal Basilica under Bishop Theodore marked the city as an important religious center. However, the city's decline began after being sacked by Attila the Hun in 452 AD. Aquileia remained a religious center, though its military significance waned. Over time, the patriarchal seat moved to Cividale del Friuli for greater security. In the 8th century, Aquileia's significance was further diminished, but the city experienced a revival around the year 1000.

The remains of ancient Aquileia, known as the "Archaeological Area of Aquileia and the Patriarchal Basilica," have been part of the UNESCO World Heritage List since 1998. The Museo Archeologico Nazionale di Aquileia, situated in the modern town, showcases archaeological artifacts from the ancient city.

Overview In 452 AD, it was destroyed by the hordes of Attila's Huns.

This is how Herodian describes it at the time of his 238 siege by the troops of Maximinus Thrax:

Republican period (181-31 BC). Aquileia was founded in 181 B.C. near the Natissa River as a colony under Latin law,Velleius Paterculus, Historiae Romanae ad M. Vinicium libri duo, I, 13.2. by Lucius Manlius Acidinus, Publius Scipio Nasica and Gaius Flaminius, sent by the senate to bar the way to the neighboring Carni and Histrian peoples who threatened the eastern borders of Italy.Livy, Ab Urbe condita libri, XXXIX, 55; XL, 34.2-3; XLI, 1; XLI, 9-10; XLIII, 1. It was established in the territory of the Carni:Pliny the Elder, Naturalis historia, III, 126-127.

The first settlers were 3,000 veterans, followed by their respective families from Samnium, a total of about 20,000 people, who were followed by groups of Veneti; later, in 169 B.C., another 1,500 families were added,Livy, Ab Urbe condita libri, XLIII, 17.1. while eastern communities, such as Egyptians, Jews and Syrians, also settled in the city.

It was ruled initially by duumvirs and later by quattuorviri with its own senate.Luisa Bertacchi, Aquileia: l'organizzazione urbanistica, p.209. The city first grew as a military outpost in preparation for future campaigns against Histri and Carni, later as "headquarters" for eventual Roman expansion toward the Danube.

Aquileia formed the main base of the military operations in Illyricum of the consuls Lucius Cornelius Lentulus Lupus, Gaius Marcius Figulus, and Publius Cornelius Scipio Nasica Corculum, during the years 156-155 BC, against the Dalmatian tribes, which then led to the conquest of the city of Delminium.Appian of Alexandria, The Illyrian Wars, 11. In 129 B.C. consul Gaius Sempronius Tuditanus attacked the Histrian peoples of Iapodes and Liburni from northern Italy (from his "headquarters" in Aquileia, as reflected in a eulogy dedicated to him),.Pliny the Elder, Naturalis historia, III, 129. and later also defeated the Alpine peoples of the Carni and Taurisci (from the area of Nauportus), earning for these successes the Triumph.Fasti triumphales: . Ten years later, in 119 BC. Lucius Caecilius Metellus completed a new victorious campaign against the Dalmatians, using Aquileia as the base of his operations,Massimiliano Pavan, Aquileia città di frontiera, in Dall'Adriatico al Danubio, Padova 1991, p.126. celebrating his triumph the following yearFasti triumphales 625 anni ab Urbe condita. and earning himself the victorious title of Delmaticus.Appian of Alexandria, The Illyrian Wars, 11 and 33; Livy, Periochae 62; Eutropius, Breviarium ab Urbe condita, IV, 23.2. Four years later, in 115 BC, the consul Marcus Aemilius Scaurus operated in Cisalpine Gaul against both the Ligurians in the west and the Carni and Taurisci in the east, using Aquileia, in the latter case, as his "headquarters."Aurelius Victor, De Viris Illustribus, 72.7. Still two years later, in 113 B.C., the consul Gnaeus Papirius Carbo was sent to confront an invasion of Germanic-Celtic peoples (including the Cimbri), who had penetrated Illyricum and then Noricum. Carbo, at the head of an army that had Aquileia as its headquarters,Appian of Alexandria, Celtic Wars, 13; Strabo, Geographica, V, 1.8. was however defeated near Noreia.

From its origin as a military base derives the four-sided shape of the garrison, divided by the cardo maximus, today's Via Julia Augusta, and the decumanus maximus. Once the region had been pacified and Romanized, the city, a municipium after 89 B.C. as a result of the lex Iulia de civitate (which conferred the fullness of Roman law, assigning it to the Velina tribe),. grew larger in successive stages, as attested by the various city walls. It became a political-administrative center (capital of the Tenth Augustan Region, Venetia et Histria) and a prosperous emporium, benefiting from the long port system and the radius of important roads that ran from it both northward, beyond the Alps and as far as the Baltic Sea ("amber road"), and latitudinally, from Gaul to the East. From late Republican times and throughout most of the Imperial era Aquileia constituted one of the great nerve centers of the Roman Empire.Massimiliano Pavan, Aquileia città di frontiera, in Dall'Adriatico al Danubio, Padova 1991, p.124. Notable was its artistic life, sustained by the wealth of patrons and the intensity of trade and contacts. Its location made the city a crossroads of trade in glass, iron and amber; a wine named Pucinum was also produced.

It was precisely during this period that Aquileia gained increasing strategic-military importance. It was to serve as an advanced post protecting northern Italy against possible invasions from the north and east, as happened: at the time of the Cimbrian Wars in 102 BCE;A.Degrassi, Per quale via i Cimbri calarono nella Val Padana, in Scritti vari di antichità, II, Roma 1962, pp.991 seg. when Mithridates VI of Pontus planned an invasion of the peninsula through an alliance with Gauls and Scythians. He hoped that many of the Italic peoples would ally with him in hatred of the Romans, as had happened during the Second Punic War to Hannibal, after the Romans had waged war against him in Spain. He knew, moreover, that almost all of Italy had rebelled against the Romans on two occasions in the last thirty years: at the time of the social war of 90-88 B.C. and in the gladiator Spartacus' servile war of 73-71 B.C.Appian of Alexandria, Mithridatic Wars, 109; Strabo, Geographica, VII, 4.3; Plutarch, Life of Pompey, 41.2; Cassius Dio, XXXVII, 11.1. for the formation of the powerful kingdom of the Dacian tribes by their king Burebista.Strabo, Geographica, VII, 3, 11.

During his first consulship in 59 B.C., Gaius Julius Caesar, with the support of the other triumvirs (Pompey and Crassus), obtained by the Lex Vatinia of March 1The Lex Vatinia was proposed by the tribune of the plebs Publius Vatinius, who would later be Caesar's lieutenant in Gaul the proconsulate of the provinces of Cisalpine GaulCisalpine Gaul corresponded to the territories of the Po Valley between the Oglio River and the Piedmont Alps and Illyricum for five years and the command of an army consisting of three legions.The three legions entrusted to Caesar by the Lex Vatinia were VII, VIII and VIIII. Shortly afterwards a senatus consultum also added that of Gallia Narbonensis,The province of Gallia Narbonensis had been established in 121 B.C. and included the entire coastal strip and Rhone valley, in present-day Provence (which precisely from provincia derives its name) and Languedoc whose proconsul had died suddenly, and the command of the 10th legion.Lawrence Keppie (in The making of the roman army, from Republic to Empire, Oklahoma 1998, pp. 80-81) assumes that the 10th legion was positioned in the capital of Gallia Narbonensis, Narbonne.

The fact that Caesar was initially assigned the province of Illyricum as part of his imperium, and that by early 58 BCE as many as three legions had been stationed in Aquileia,Caesar, Commentarii de bello Gallico, I, 10. may indicate that he intended to seek glory and riches in this very area with which to increase his military and political power and influence. Caesar needed major military victories so that he could build up his own personal power with which to counterbalance that which Pompey had built up through his victories in the East. To this end he probably planned a campaign beyond the Carnic Alps all the way to the Danube, taking advantage of the growing threat from the tribes of Dacia (roughly corresponding to present-day Romania), which had united under the leadership of Burebista, who had then led his people to conquer the territories located west of the Tisza River, crossing the Danube and subduing the entire area over which the present Hungarian plain stretches, but above all coming dangerously close to Roman Illyricum and Italy. However, his armies had come to a sudden halt, perhaps out of fear of a possible direct intervention by Rome in the Balkan-Carpathian area. Thus, instead of continuing on his march westward, Burebista had returned to his bases in Transylvania, then turned his sights eastward: he attacked the Bastarnae and finally besieged and destroyed the ancient Greek colony of Olbia (near present-day Odessa).J.Carcopino, Giulio Cesare, Milano 1981, pp.255-260; A.Piganiol, Le conquiste dei Romani, Milano 1989, pp.432-433.

Caesar visited Aquileia several times during the conquest of Gaul: in the winter of 57-56 BC, in connection with military/diplomatic operations conducted by the proconsul himself in the vicinity of Salona around March 3 of that year;Cicero, In P. Vatinium ("Against Publius Vatinus"), 38; Cesare, De bello Gallico, II, 35 e III, 7. in 54 BC to conduct a brief campaign against the Pyrasti people who inhabited southern Illyricum;Caesar, De bello Gallico, V, 1, 5-9. again in the winters of 54-53 BC. B.C.Caesar, De bello Gallico, VI, 44. and 53-52 B.C.;Caesar, De bello Gallico, VII, 1.1. Caesar returned with the legio XV during the following winter, after the city had been attacked along with Tergeste by the Iapydes,Aulus Hirtius, De bello Gallico, VIII, 24.3Appian of Alexandria, The Illyrian Wars, 18 and 52. when the proconsul was engaged in Gaul against Vercingetorix. The consequence was that the inhabitants of Aquileia were not only forced to repair the damaged walls, but began the construction of two defensive castella: at Tricesimo (50 km north of Aquileia). and at Iulium Carnicum.A.Degrassi, Per quale via i Cimbri calarono nella Val Padana, in Scritti vari di antichità, II, Roma 1962, pp.36 seg.

In 49 BC, at the outbreak of civil war, Aulus Gabinius was recalled by Caesar and given command of operations in Illyricum. He had three new legions at Aquileia (XXXIII, XXXIV, and XXXV, amounting to 30 total cohorts)H.Parker, Roman legions, pp.64-65. and at the head of 15 cohorts and 3,000 cavalry, marching south toward Macedonia, he suffered a sudden attack by the Dalmatians, managing to shelter at Salona with only a few survivors.Appian of Alexandria, The Illyrian Wars, 12. Eventually he was able to join Lucius Cornificius (who had Legions XXXI and XXXII under his employ) with the few remaining soldiers to fight against these peoples.