The Quadi were a smaller Germanic tribe, about which little definitive information is known. The history of non-literate peoples is written by their opponents, and we can only know the Germanic tribe the Romans called the 'Quadi' through Roman eyes. No pottery style or other remains of material culture serve to distinguish Quadi encampments from those of closely related groups.
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 BCE, briefly documented by Tacitus in his Germania. A further Marcomannic confederation that included the Quadi fought the future emperor Tiberius in 6 CE.
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 (Srabo wrote in Greek). Part of their range is Bohemia, the domain of Marabodus. 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.
A couple of 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. The Quadi were 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 was planning to advance the Roman border east and north to the Carpathian Mountains and Bohemia when he became ill and died in 180.
Ancient Germanic peoples | Ancient Roman enemies and allies | Ethnic groups in Europe