In 374 the Quadi, a German tribe in what is now Moravia and Hungary, resenting the erection of Roman forts to the north of the Danube in what they considered to be their own territory, and further exasperated by the treacherous murder of their king, Gabinius, crossed the river and laid waste the province of Pannonia.
In the autumn of 169 two of the German tribes, the Quadi and the Marcomanni, with their allies the Vandals, Iazyges and Sarmatians, renewed hostilities and, for three years, Aurelius resided almost constantly at Carnuntum.
In 174 Aurelius gained over the Quadi a decisive victory, which is commemorated by one of the sculptures on the column of Antonine.
Commodus, who was with his father when he died, erected to his memory the Antonine column (now in the Piazza Colonna at Rome), round the shaft of which are sculptures in relief commemorating the miracle of the Thundering Legion and the various victories of Aurelius over the Quadi and the Marcomanni.
He defeated the Chatti, annexed the district of the Taunus, and established the Limes as a line of defence; but he suffered defeats at the hands of the Quadi, Sarmatae and ' Marcomanni; in Dacia he received a severe check, and was obliged to purchase peace (90) from Decebalus by the payment of a large sum of money and by guaranteeing a yearly tribute - the first instance in Roman history.
The proximity of dangerous barbarian tribes (Quadi, Marcomanni) necessitated the presence of a large number of troops (seven legions in later times), and numerous fortresses were built on the bank of the Danube.
Having defeated the Quadi and Sarmatians on the Danube, Carus proceeded through Thrace and Asia Minor, conquered Mesopotamia, pressed on to Seleucia and Ctesiphon, and carried his arms beyond the Tigris.
The Quadi are said to have considered their swords divine.
Most likely they were descendants of the Marcomanni, Quadi and Narisci, tribes of the Suevic or Swabian race, with possibly a small intermixture of Gothic or Celtic elements.
The Quadi were settled somewhat farther east about the source of the Elbe.
SUEBI, or SuEVI, a collective term applied to a number of peoples in central Germany, the chief of whom appear to have been the Marcomanni, Quadi, Hermunduri, Semnones and Langobardi.
The Marcomanni occupied the basin of the Saale, but under their king, Maroboduus, they moved into Bohemia during the early part of Augustus's reign, while the Quadi, who are first mentioned in the time of Tiberius, lay farther east towards the sources of the Elbe.
The part of the country north of the Danube was peopled by the Marcomanni and the Quadi, and both of these tribes were frequently at war with the Romans, especially during the reign of the emperor Marcus Aurelius, who died at Vindobona in A.D.