Europe 406: Crossing of the Rhine
Stilicho’s focus on fighting first Alaric (401–2) and then Radagaisus (405–6) in Italy had left the Roman defences in Gaul dangerously neglected. In late 406, taking advantage of this situation, a force of Vandals, Alans, and Suebi defeated the Roman-allied Franks and invaded the Western Empire by crossing the Rhine near Mogontiacum (Mainz).
?–23 Aug 406 Battle of Faesulae▲
Following their defeat outside Florentia (Florence), Radagaisus and his Goths fled to the nearby hills around Faesulae (Fiesole), where they were quickly blockaded by the Roman army. After holding out for some time, and with his men on the brink of starvation, Radagaisus attempted to slip through Roman lines but was captured and, on 23 August 406, executed. With their king lost, his surviving followers surrendered; some 12,000 were incorporated into the Roman auxiliaries while the remainder were sold into slavery, apparently in such large numbers that the slave market collapsed.
406–411 Pharsman IV and Mihrdat IV▲
During his reign (406–409) Pharsman IV, the pious Christian ruler of the Kingdom of Iberia, rejected the suzerainty of Sasanian Persia and ended tribute payments to the Shah Yazdegerd I. Pharsman’s brother and successor, Mihrdat IV, was, however, a less able ruler and soon alienated not just the Persians, but also the Romans. In 411 he was defeated and captured by the Sasanian army, who replaced him with a more compliant king, Archil (411–435).
Oct 406 Gratian of Britain▲
After murdering the usurper Marcus in c. October 406, Roman troops in Britain proclaimed Gratian, a British native, as Emperor in his place. Little is known of Gratian, but he was probably the same person as the legendary Gracianus Municeps, who, according to the unreliable Geoffrey of Monmouth (12th C), defeated the Picts before beginning a reign of terror on the island. Regardless of the truth of this story, Gratian held onto power for four months, until early 407, when he was overthrown and killed in favor of Constantine III.
31 Dec 406 Crossing of the Rhine▲
On 31 December 406 a large party of Hasding Vandals, Siling Vandals, and Alans crossed the Rhine near Mogontiacum (Mainz) and invaded Roman Gaul. They were accompanied by the Suebi—a collection of Germanic tribes that included members of the Marcomanni, Quadi, and Alemanni—and small numbers of other peoples, including Sarmatians, Gepids, and Herulians. Having already defeated the neighboring Franks and catching the depleted Roman garrisons by surprise, the invaders quickly stormed Mogontiacum before overrunning the region.