The record is incomplete. The bulk of historical information about the Chauci is from the
Annals of
Tacitus, written in 117. Many parts of his works have not survived, including an entire section covering the years AD 38–46, as well as the years after AD 69. The earliest mention of the Chauci is from 12 BC and suggests that they were assisting other Germanic tribes in a war against the
Romans.
Drusus campaigned against those Germans along the lower Rhine, and after devastating the lands west and north of the Rhine he won over (or defeated or intimidated) the
Frisians. He was in the process of attacking the Chauci when his vessels were trapped by an
ebb tide. Drusus gave up the attack and withdrew.
Aftermath of Teutoburg Forest, c. 15 The Germans under
Arminius had destroyed 3
Roman legions under
Varus at the
Battle of the Teutoburg Forest in AD 9. The Romans recoiled at first but then
Germanicus initiated destructive campaigns against those Germans whom the Romans blamed for their defeat. The Chauci were not among them, and were said to have promised aid, and were associated with the Romans in "military fellowship". However, in defeating Arminius' own tribe (the
Cherusci) the Romans were unable to capture or kill Arminius, who escaped. There were Chauci among the Roman auxiliaries, and they were rumored to have allowed the escape. In one of the campaigns a Roman fleet (probably riverine, not ocean-going) was broken up by a storm, causing many casualties. Germanicus himself managed to survive by reaching the lands of the Chauci, who provided him with a safe haven. Germanicus' campaigns had resulted in recovery of two of three Aquila lost in the
Battle of the Teutoburg Forest defeat; the third legionary standard was recovered in AD 41 by Publius Gabinius from the Chauci during the reign of
Claudius, brother of Germanicus. A parenthetical note concerns the
Ampsivarii. They had not supported the German cause led by Arminius in 9 AD and had been ostracized as a result. The Chauci had suffered no such disaffection from the other Germanic tribes in the aftermath of Teutoburg Forest, nor had they alienated the Romans. Many years later, , the Chauci seized upon an opportunity to expel the Ampsivarii and occupy their lands at the mouth of the
River Ems, whereby they gained a border with the Frisians to the west.
Roman war against Gannascus, c. 47 (Rhine flotilla) in the first century AD. In AD 47 (and perhaps for some time earlier), the Chauci along with the Frisians were led by a certain
Gannascus of the
Canninefates. They raided along the then-wealthy coast of
Gallia Belgica (i.e., the land south of the
Rhine and north of the Rivers
Marne and
Seine), and the Chauci made inroads into the region that would later become the neighbouring Roman province of
Germania Inferior, in the area of the Rhine delta in what is now the southern Netherlands.
Corbulo was made the local Roman military commander. He successfully engaged the Germans on both land and water, occupied the Rhine with his
triremes and sent his smaller vessels up the estuaries and canals. The Germanic flotilla was destroyed in a naval engagement, Gannascus was driven out, and Frisian territory was forcibly occupied. A negotiation between the Romans and Gannascus was arranged under the auspices of the 'Greater Chauci', which the Romans used as an opportunity to assassinate their opponent. The Chauci were outraged by the act of
bad faith, so the emperor
Claudius forbade further attacks on the Germans in an effort to ease tensions, and the Romans withdrew to the Rhine.
Batavian Revolt, c. 69 In AD 69 the
Batavi and other tribes rose against Roman rule in the
Revolt of the Batavi, becoming a general uprising by all the Germans in the region. Led by
Civilis, they inflicted huge casualties on the Romans, including the destruction of a Roman fleet by a Germanic one off the
North Sea coast. Led by
Cerialis, the Romans gave as good as they had gotten, ultimately forcing a humiliating peace on the Batavi and stationing a legion on their territory. Both the Chauci and the Frisians had auxiliaries serving under the Romans, and in a siege and assault by Civilis at
Colonia Claudia Ara Agrippinensis (at modern
Cologne), a
cohort of Chauci and Frisians had been trapped and burned. The Chauci had supported Civilis in their own name, providing him with reinforcements. ==Sea raiding==