It is important that you realise from the start that we will NEVER know ‘the truth’ about Claudius. There is no ‘real’ Claudius, only constructs.
Very little remains of Claudius from the time, apart from coins and inscriptions. All the original written sources have been lost, and it is impossible even to guess what they said. Claudius is supposed to have written a History, but if he did it was so obscure or ineffectual that no personal or positive aspects of his reign have passed from it into the record. Also there is no reference to Cluvius or Fabius Rusticus as a source for Claudius’s reign, so either they didn't write about him, or what they wrote has been lost in transmission.
We DO possess one account of Claudius from shortly after his reign – Seneca’s Apocolocyntosis (‘Pumpkinification’) – a savage satire on Claudius’s deification, which portrays Claudius as a cruel yet stupid tyrant. Seneca personally hated Claudius, and in Nero’s reign it was wise to do so anyway; so this interpretation is as much use to historians as Spitting Image.
By contrast, Pliny’s Natural History (written after Vespasian, when it was OK to praise Claudius) contains a number of positive references – e.g. the growth of Rome’s empire and Claudius’s public works – but even Pliny deplores Claudius’s promotion of freedmen and his elevation of Messalina and Agrippina. Roman history was written by Roman nobles, and they could never applaud Claudius for taking power away from them.
The main sources – Tacitus, Suetonius and Dio
Criticism reaches a crescendo in Tacitus. In his recent analysis of Tacitus’s Claudius, SJV Malloch (2009) finds a Tacitus-Claudius who is so passive that he disappears altogether from the story … which is almost wholly, firstly about Messalina and Narcissus, and then about Agrippina. Behind this lay a Tacitean theme of the ever-growing evil of tyranny, and Claudius comes out of Tacitus very badly - as ruler who is at the same time weak and unjust.
According to Donna Hurley (2001), Suetonius’s account ‘judges Claudius more harshly than Tacitus’. After a survey of Claudius’s reign which is generally positive, Suetonius uses anecdote and allegation to launch a withering attack on Claudius’s character, stigmatising him as foolish, timid, bloodthirsty … and totally dominated by his wives and freedmen. Suetonius-Claudius turns out to be a Jekyll-and-Hyde character, with two sides it is impossible to reconcile.
Dio’s account of Claudius has been lost, and survives only in epitome (i.e. in a summary made by medieval writers). Hurley considers it ‘relatively kind to Claudius’, but basically it repeats the paradox established by Tacitus and Suetonius – of a ruler in whose reign good things happened … but who at the same time seems to have been a passive tool of others.
The ‘problem of Claudius’
Since Tacitus, Suetonius and Dio are the only real sources we have for Claudius, historians ever since have got trapped by what one historian has called ‘the problem of Claudius’ - viz., given the apparent contradictions of character, what was Claudius really like?
I suppose it depends on how you interpret the sources. In the 18th century, Edward Gibbon labelled him ‘the stupid Claudius’. The English scholar William Smith (1849) tried to be kinder but failed, suggesting that a youthful illness had left Claudius ‘deficient in judgement, tact and presence of mind’. In 1882, the German historian Theodor Mommsen was dismissive: ‘mildly deranged … insignificant … with no will of his own’.
In the 1930s, however, as Europe fell under the power of tyranny and Italy tried to rebuild her empire, attitudes to Claudius changed. The works of Italian historian Arnaldo Momigliano and Robert Graves’s novel I Claudius are very different in nature, but they share certain features. Both presented Claudius as a ‘would-be Republican’, who took the principate unwillingly. They also presented him as being a good deal cleverer than people thought at the time. Archaeological discoveries – notably a letter of Claudius about Judea – supported their case. If you ditch the character-assassination of the original sources, it is possible to portray Claudius as a reformer, running an effective government.
Fergus Millar (1977) sought to solve the problem of Claudius by concentrating, not on Claudius’s reputation in the sources, but on his actions – he coined the memorable phrase: ‘the emperor was what the emperor did’. He destroyed the idea of a centralised, departmentalised administration, and argued that Claudius's freedmen were less like modern civil servants, and more advisers and friends. Consequently, he returned to a Claudius who was passive and reactive. By contrast Barbara Levick (1990) – in what you need to realise is generally accepted as the definitive modern study of Claudius – suggested that Claudius’s reign was ‘the turning point in the establishment of the permanent monarchy.’
The supremacy of Image
Just as Judith Ginsberg asserted that we cannot know what Agrippina was like, only how she has been portrayed, the latest study of Claudius – by Josiah Osgood (2011) – believes that the nature of the sources means that ‘true biography of almost any emperor is unfeasible’. Osgood reminds us that an emperor had not only to be a ruler, but also to fulfill for his subjects a wide range of symbolic roles (not least that of a god) and he looks at Claudius’s IMAGE (on statues and coins) rather than trying to synthesise any construct of ‘a real Claudius’.
So will it always be impossible to say what Claudius was like? It is irresistibly tempting to try! You must surely have your own putative constructs. I tend to read Claudius as a first-century Henry VIII, plagued by problems with his wives and the succession, but bringing in (despised) ‘new men’ to replace the old aristocratic model with a modernising, more efficient monarchical regime ... and using force if necessary.
But such parallels, I am afraid, might be useful to highlight certain aspects of Claudius’s reign, but they cannot define what that reign was like.
The sad truth is that we will only ever know how Claudius has been portrayed.