the fact that the people who were called Picts were a fundamentally heterogeneous group with little in the way of cultural uniformity. Care needs to be taken to avoid viewing the subject through the lens of what Gilbert Márkus calls the Ethnic Fallacy. The people who were first called "Picts" were very different from those of the later period, in terms of language, culture, religion and politics. The term "Pict" originated around the 3rd century AD as a generalised exonym used by the Romans to describe those Britons north of the Forth–Clyde isthmus. The term is most likely to have been intended as a pejorative, deriding the perceived barbarism of an unromanised people. Picts continued to be used by outsiders, notably the Irish Annalists and contemporary scholars like Bede, to describe the peoples of North and Eastern Scotland, excluding the Dál Riatans, the Britons of South Western Scotland and the Northumbrian Angles to the South East, into Lothian. A unified identity appears to have consolidated with the expansion of the Verturian hegemony in the late seventh century, and this continued to the ninth century, following the complete Gaelicisation of the Picts and merging with the Kingdom of Dál Riata. The Latin word first occurs in a panegyric, a formal eulogising speech from 297 AD and is most commonly explained as meaning "painted" (from Latin 'to paint'; , 'painted', cf. Greek , 'picture'). Julius Caesar and Pliny the Elder reported in the first centuries B.C.-A.D. that the Celtic peoples of the British Isles would paint themselves in various terms that are now translated as "woad", but originally may have meant "glass" and "green" (vitrum and glastum, respectively). Woad; a plant that produces indigo dye when its leaves are crushed, soaked in water, fermented, and mixed with a strong base; is native to Europe, Central Asia, and the Mediterranean; and has been used as a source of dye since ancient times. Tattooing has been known across indigenous cultures worldwide, including Europe as seen in the Ötzi bog body discovered in the Alps, home of the Proto-Celtic Hallstatt culture. Therefore, the references to the Celtic British warriors encountered by the Romans are generally understood to be a reference either to the Pictish practice of tattooing; or to painting themselves blue and green. The pigments for these tattoos and paints could have been derived from woad and other plants, or from copper and iron