Tiberius Claudius Nero Germanicus was born in Lyon, France (ancient Lugdunum) in 10 B.C. He was the youngest son of Drusus and Antonia the Younger (the niece of Augustus and daughter of Marc Antony). Due to poor health and a pronounced stammer, his family assumed that he would never achieve success. According to Suetonius (Lives of the Caesars: Claudius, III,2), even his own mother considered him "a monster, a man whom Mother Nature had begun to work upon but then flung aside." He was not granted any major position during the reigns of Augustus or Tiberius, but in 37 A.D., during the reign of his nephew Caligula, he shared the consulate and presided at the public games in the Emperor's absence. Claudius was possibly involved in the plot to assassinate Caligula, and he succeeded his nephew at the age of 51 as the fourth Emperor of Rome on 24 January 41 A.D. (see Kleiner, Roman Sculpture, pp. 129-134 and Varner, ed., From Caligula to Constantine: Tyranny & Transformation in Roman Portraiture, p. 114).
In 43 A.D. Claudius ordered the invasion of Britain by a force of 40,000 soldiers. Following the successful campaign, Camulodunum (Colchester) was made the capital. After his murder in 54 A.D., Claudius was deified by a decree of the Senate under Nero. A temple was begun at Camulodunum in his honor, but was destroyed during the Boudican revolt of 60 A.D. Another was completed in Rome by Vespasian.
The presence of the radiate crown worn by Claudius on the Stamford Bridge Tondo suggests that, like the temples dedicated in his honor, this portrait was a posthumous creation, as Claudius's successor Nero was the first Roman emperor represented wearing such a crown during his lifetime (see Varner, op. cit., p. 128). The discovery of the Stamford Bridge Tondo in Yorkshire attests to Claudius's popularity in Britain. Its original function is unknown.
For another imago clipeata of Claudius now in the Louvre see p. 166 in Massner, "Zum Stilwandel im Kaiserporträt claudisher Zeit" in Die Regierungszeit des Kaisers Claudius (41-54 n. Chr.).