Picts, the original Blue Man Group.

Ah yes, the mysterious Picts. Who could forget the memorable interpretation of them in Robert E. Howard's Conan series? Devolved painted barbarians speaking a guttural tongue and could kill you as soon as look at you... Roman interpretations of them being naked savages... Confused Irish accounts of them being lost Scythians... According to long outdated encyclopedias, they were "Mediterraneans" devolved into a lesser race that hid in caves under the hills of Scotland, and were wiped out by the invading Vikings and Gaels.

A Pict according to the makers of Conan the Barbarian, THE MOVIE. (Nice handlebars. Looks like a Victorian Brit gone native.)

Picts of the Bran Mak Morn series. Also by Howard.

Actually they were kin to the Welsh and had several civilized kingdoms in Alba (as Scotland was the called.). Yes it's true they painted themselves in blue woad, but so did every other Celt. Yes they fought naked, but so did...well, actually only one in every other group of Celts fought like that. The biggest kingdoms were Cat (Caithness) in the furthest north, from whom the clans of the Chattan Confederation claimed descent (Cat-Catti-Chattan). It's also where they got their symbol (the cat) from. This kingdom was destroyed by the Vikings and Madoc, last Pictish King of Cat, fled south to Moray and from his son the Chattan confederation gets it's heritage.

The second major kingdom was Fortriu, or Moray. This kingdom lasted until it was absorbed (by marriage and family ties) into the Gaelic Kingdom of Dalriada. The Picts were never destroyed, (I ought to know, I'm descended from a Pictish clan.), they just stopped calling themselves "Picts" when the whole kingdom became "Scots". The royal line of medieval Scotland was both Gael and Pict. Pict is a Roman term applied to these northernmost Britons. It simply means "painted". They were called Cruithni by the Irish (a corruption of what the Picts called themselves, Britons. Oh wait! Who else call themselves Britons? WELSH!!), and Caledonii (also by the Romans.). So simply put there's nothing mysterious at all about them. They're Celts. And they're still with us today.

More Hollywood Picts from the movie King Arthur. (The one in the middle is the Druid Merlin.)

Real, historical, Picts. Funny how they don't look much different from the other Britons/Scots. 

Caledonian Picts charging the Roman lines near Mons Graupius.

A Victorian Pict. Not far off the mark.

Pictish symbol of unknown meaning, officially termed a double disc and z rod. Looks like a lightning bolt to me.

Pictish stag.