A sceptical report of wildmen seen in pre-Roman Britain in AD16?

A wildman on the porch of the church at Peasenhall, Suffolk. It dates from around 1490.

I found what's likely to be the earliest surviving reference to wildmen in England – or at least possibly in what's now England or possibly somewhere on the North Sea coast. The source is from way back in around 116AD, describing alleged events a century earlier.

The Annals, written by the Roman historian and senator Publius Conrelius Tacitus, describes the reigns of the early Roman emperors Tiberius and Nero. It covers the period from AD14 to AD68. The Annals was written around 116AD, so around a century after the events it describes, possibly using as a source the Acta Senatus, the records of the Roman senate, to which he would have had access to as a Roman senator.

In the Annals Book 2, 23-24 there is an account of a Roman fleet commanded by the general Germanicus Julius Caesar, nephew and adopted son of the Emperor Tiberius, in 16AD. This fleet was transporting legions returning from campaigns against German tribes and going back to their forts in the province of Germania Inferior (the southwestern part of what’s now the Netherlands up to the Rhine and parts of Germany and Belgium).

Long before the canals linking the interior to the North Sea were constructed, this required the fleet to sail up the River Ems (now on the Dutch-German border on the Fresian coast), sail into the North Sea and then make the dangerous journey along the treacherous Dutch coast before entering the River Schelde and returning to base. The fleet of Germanicus was blown off course, some troops were left marooned on islands in the Waddenzee around the Dutch coast or even blown all the way to Britannia (then still outside the Roman Empire), these troops were later returned to Roman territory, sent by boat by British "local chieftains."

Tacitus describes how shipwrecked Roman legionaries and sailors who had been blown off course to the "distant regions told the most amazing stories; enormous tornados, birds that nobody had ever heard of before, sea monsters, and enigmatic forms that were half man and half beast: they had seen or imagined them in their terror." Tacitus was apparently of the opinion that soldiers and sailors in the service of Roman had imagined such horrors as "half men, half beast" while suffering from what we would now call PSTD. At the time that Tacitus was writing, Britannia had been largely brought under Roman rule, and while it was known to be populated with "barbarians", Romans knew there were no wildmen to be found there. However, in the days of Germanus's expedition, the thought of setting foot in the wild, unknown land of Britannia, beyond the edge of the known world, induced terror.

So in the early days of the Roman Empire, there were already stories of wildmen, "half man and half beast" living on what was seen as the edge of the world, with at least one author showing scepticism about such tales. This is at least 800 years before the first evidence for Western European Wildman traditions.