A ‘medieval map’ of the British Isles from a literary forgery

A 19th century copy of a map drawn and engraved by Charles Bertram in 1755, which he claimed came from a medieval manuscript, composed by Richard of Westminster. Orientated with north to the left, it marks the British tribes and Roman roads.
In 1747 Charles Bertram (1723-65), a teacher of English language in the Royal Marine Academy of Copenhagen, wrote to William Stukeley (1687-1765, an antiquarian famed for his archaeological studies of Stonehenge and Avebury) describing the manuscript history of Roman Britain, which was accompanied with an 'antient map'. With Stukeley on the hook, Bertram delayed sending him further details, claiming an associate, 'wild in his youth, had stolen it out of a larger manuscript in an English Library' and had sworn him to secrecy. Bertram began sending extracts of the text in several letters, as well as a copy of the map.
After studying the text, Stukeley identified Richard of Westminster as Benedictine historian Richard of Circencester (c.1340-1400), who worked at Westminster Abbey. Richard was already known for 'De Situ Britanniae' (On the Situation of Britain), which used Roman texts, but Bertram's manuscript offered new information, including new Roman towns as two Roman provinces in Scotland, Valentia & Vespasiana. Stukeley presented his analysis of the text to the Society of Antiquaries in 1756 and Bertram published 'De Situ Britanniae' (On the Situation of Britain) in Copenhagen the following year and 'Britannicarum Gentium Historiae Antiquae Scriptores Tres' (Three Ancient Writers on the History of the British People) in 1779.
The publications were highly influential (popularising the name 'Pennines' for the mountain chain) and any scholarly rejection was aimed at Richard's writing rather the authenticity of the text. In 1809 Bertram's original 'De Situ Britanniae' was difficult to obtain, so Henry Hatcher published an English translation, 'The Description of Britain', in which this map appeared.
It was still half-a-century before the forgery was uncovered. In the 1860s Bernard Bolingbroke Woodward, librarian-in-ordinary to the Queen, studied the text and published a series of articles pointing out the anomalies. He wrote that the text was 'more or less good idiomatic English put into Latin words, and apparently by the help of a dictionary', and based on 'a very badly edited printed [edition of Tacitus], one of the 17th or 18th century'. There were placenames that were linguistically medieval and mistakes that Camden had introduced in the 16th century. Woodward concluded that 'De Situ Britanniae had 'every mark of being the production of such a man as Bertram translating bad English into worse Latin'.