The Quadi were a smaller Germanic tribe, about which little is definitively known. We only know the Germanic tribe the Romans called the 'Quadi' through reports of the Romans themselves. No pottery style or other remains of material culture serve to distinguish Quadi encampments from those of closely related groups.
1st century BC/AD 
In the 1st century BC, according to Roman written sources, the Quadi were migrating alongside the more numerous Marcomanni, whose name simply means the "men of the borderlands" living on the frontiers of Germany, where it was bordered by the River Danube, south of which lay Roman territory.
Perhaps originating north of the River Main, the Quadi and Marcomanni migrated into what is now Moravia, western Slovakia and Lower Austria where they displaced Celtic cultures and were first noticed by Romans in 8–6 BC, briefly documented by Tacitus in his Germania. A further Marcomannic confederation that included the Quadi fought the future emperor Tiberius in 6 AD.
There may be an earlier reference to the Quadi in the Geography of Strabo (7.1.3). In a parenthetical expression, often removed from the main text, he mentions a branch of the Suevi called the Koldouoi, transliterated to Latin Coldui (Strabo wrote in Greek). Part of their range is Bohemia, the domain of Maroboduus. The emendment of Coldui to Coadui (Quadi) is generally considered correct.
Tacitus in Germania only mentions the Quadi in the same breath as the Marcomanni, alike in warlike spirit, alike governed by "kings" of their own noble stock, "descended from the noble line of Maroboduus and Tudrus," the "Tudric" line apparently kings among the Quadi. The royal powers of both tribes were also alike, according to Tacitus, in being supported by Roman silver.
Their frontiers for the next 350 years or more were the Marcomanni to the west, proto-Slavic tribes to the north, Sarmatian Iazgyians and Asding Vandals arriving to the east somewhat later, and the Roman Empire to the south.
2nd century AD 
In the later 2nd century AD, Marcus Aurelius fought them in the Marcomannic Wars, for which our source is an abridgement of lost books of Dio Cassius' history. The troubles began in late 166 when the Langobardi (the Lombards) and Ubii crossed the Danube into Roman Moesia. They must have done so with the consent of the Quadi, through whose territory they had to cross. Presumably the Quadi wished to avoid trouble themselves by allowing these tribes to pass through into Roman territory. This invasion was apparently thrown back into Quadi territory without too much difficulty as far as the Romans were concerned, but the incursion marked the start of a long series of attempts to cross the border.
A few years later, the Marcomanni and Quadi, with assistance from other tribes that had crossed the Danube, overwhelmed a Roman army, passed over the plain at the head of the Adriatic, and put the town of Aquileia in northern Italy under siege. After initial Roman losses, the Marcomanni were defeated in 171, and Marcus Aurelius managed to make peace with some of the tribes along the Danube, including the Quadi. But in 172, he launched a major attack into the territory of the Marcomanni, and then turned on the Quadi, who had been aiding Marcomanni refugees. In a major battle in that year, his troops were almost defeated, until a sudden rain storm allowed them to defeat the Quadi  The Quadi were ultimately eliminated as a direct threat in 174. Marcus' planned counteroffensive across the Danube was prevented in 175, however, by insurrection within the Empire.
Though Marcus Aurelius successfully suppressed the revolt, it was not until 178 that he was able to pursue the Quadi over the Danube into Bohemia. He executed a successful and decisive battle against them in 179 at Laugaricio under the command of legate and procurator Marcus Valerius Maximianus of Poetovio Pannonia (modern-day Ptuj, Slovenia). He was planning to advance the Roman border east and north to the Carpathian Mountains and Bohemia when he became ill and died in 180.
3rd and 4th centuries 
In the 4th century, Valentinian spent much of his reign defending the Rhine frontier against a mixed horde of Sarmatians, Goths, and Quadi under their king Gabinius, who was slain at the treaty table by the Roman Marcellinus, son of the praefect of Gaul, Maximinus. Valentinian died in 375 after having received a deputation of Quadi to discuss a treaty. The insolent behavior of the proud barbarians so enraged the emperor, apparently, that he died of a stroke.
After the 4th century 
After about 400, the old cremation burials typical of Suevians like the Quadi disappear in Bohemia.
After crossing the Pyrenees in 409, a group of Quadi, Marcomanni, and Buri, established themselves in the Roman province of Gallaecia (modern Galicia and northern Portugal), where they were considered foederati, and founded the Suebi kingdom of Gallaecia. There, Hermeric swore fealty to the emperor in 410. Bracara Augusta, the modern city of Braga in Portugal, previously the capital of Roman Gallaecia, now became the capital of the Suebic kingdom in Gallaecia.
See also 
- List of Germanic peoples
- Migrations period
- Timeline of Germanic kingdoms
- History of Portugal
- Galicia (Spain)
- History of Spain
- 5 Dio, 72(71).3.2., 8.1.; Rubin, Z. H. (1979) "Weather Miracles under Marcus Aurelius," Athenaeum 57: 362–80; Guey, J. (1948) "Encore la 'pluie miraculeuse'," Rev. Phil. 22: 16–62; Olli, S. (1990) "A Note on the Establishment of the Date of the Rain Miracle under Marcus Aurelius," Arctos 24: 107; Israelovwich, I. (2008) "The Rain Miracle of Marcus Aurelius: (Re-)Construction of Consensus," Greece & Rome 55 (1): 85.