Unfortunately there is no definitive answer about who the ‘original’ Angus was, or even if the area was named after an actual person . Although the county of Angus went through a period of identity crisis for several centuries, when it appallingly called itself ‘Forfarshire’, common sense won through in the end and Angus became Angus again (some time around 1928). Even now, when we are lumbered with districts instead of bona fide counties, Angus is still Angus, more of less (don’t get me started on those parishes we have somehow lost to Perthshire - come back Kettins, all is forgiven!)
But who is Angus actually named after (if anyone): a person, a tribe, a god? The conservative and accepted theory says that the region was named after one of those semi-legendary ‘sons’ of the king of Erc, the Gaelic invader who seized the western seaboard of Scotland. The three sons gave their names to the three dynastic tribes of the new kingdom. But the tribe of Angus, whose heartland was Islay, was the least numerous and therefore least powerful of the kin groups. What is the chance that they were able to travel east into Pictland and carve out a territory in one of the most fertile parts of the country? Yet the River Isla, bounding the west of the county, is possibly cognate with the island Islay, named possibly after a god.
A legend set down in writing in the 12th century and contained in the geographical tract De Situ Albanie says that the kingdom was ancient divided between seven brothers, and the principal region was Angus with the Mearns. The story is a variant of an origin legend found in Ireland which named and explained the original seven Pictish regions after the sons of a mythical monarch named Cruidne, or Cruithne (meaning ‘Pict’) who reigned for a hundred years. One of the sons was named Circinn, which is understood to have comprised the later region of Angus and the Mearns. Significantly, as in the legend naming Angus, this tale confirms the prominence of Circinn. The latter ‘son’ is marked out by being described as ‘warlike’. So, at least most authorities believe that Circinn became Angus and Mearns, though it is unclear whether the place-name Angus existed before the Gaelic take over of Pictland in the 9th century, or some time later. The first mention of a region named Angus comes in the death notice of the man who ruled it. In 938 it was noted that the mormaer, or ‘great steward’, of Angus had died. This ruler, Dubucan son of Indrechtach had died one year after the Battle of Brunanburgh, a major Scottish defeat by the English. It might not be stretching supposition too far to imagine this Dubucan, a ruler or sub king, succumbed to wounds that he had sustained supporting his king in a national battle the year before.
Back to the actual name of Angus, and another possibility is that the place was named after the Pictish king Angus mac Fergus, the first of two rulers to have that name. Angus is also styled Onuist map Urguist (supposedly the original Pictish form) or Óengus mac Fergusso. Angus is thought to have come to power after a bloody four-way civil war in the early eighth century and was, as his name suggests, possibly of Irish descent. Irish sources speak of a kin-group named the Eoganacht settling in the plain of Circinn, e.g. Strathmore. After dealing with his Pictish opponents, Angus (who must have been middle aged by then) turned his attention to quelling the other nations who inhabited the space now known as Scotland. In the early 8th century it was far from clear which kingdom would come out of top and dominate the others. While the Northumbrian English had been prevented from permanent colonisation of Pictland after the battle of Nechtansmere in 685, they were still a potent force which controlled the formerly British Lothian territory. The Irish Dal Riata realm’s fortunes shrunk and contracted, according to fortune and chance, and the enigmatic British kingdom centred on Dumbarton rock, stubbornly survived in astonishing fashion for centuries after its kindred territories in northern England and the borders fell like ninepins in the early medieval era, in the face of Anglo Saxon aggression.
The bare annalistic records show that Angus was the most aggressive and successful northern warlord of his era. Following his quelling of internal opponents, Angus and his kin fought against the Dal Riata. He forced them to hand over a leader named Talorcan in 734, and this man was drowned, probably in a ritual fashion, as was an Irish ruler of Atholl five years later. Angus ruthlessly targeted the Gaelic realm in Argyll, causing it to totter on the brink of collapse for many years. He then fought against the Strathclyde Britons, allied at times with the northern English, and when he died (in 761), his reign was characterised as bloody from beginning to end.
Perhaps some might want to believe that this Angus left his name of the region of his possible origin. Others might shudder and prefer to believe the gentler fable that the county really takes its name from the Gaelic god of love.