It is here, with Geoffrey, that much of the Arthur story is founded. Born at around 1100, his book Historia Regum Britanniae, History of the Kings of Britain, was one of the most influential books of the middle ages.

From Geoffrey’s account we say that King Uther (the Pendragon) is said to have:

"conceived a violent passion for Ygerna, the wife of Gorlois, the duke of Cornwall…her husband took her away from the court without asking leave and immured her in his castle on the Tintagel headland in Cornwall…Uther sought the help of Merlin, who changed him into an exact replica of the duke…Uther freely entered the castle and slept with Ygerna. Arthur was thus begotten" (Lacy et al 1997: 37)

Geoffrey’s work is divided into twelve books of which three are concerned with King Arthur. The story goes on to reveal that Arthur became king whilst still a teenager and that he attacked and defeated the Saxons at Bath or, as we now call it, Badon. He also describes his marriage to Guinevere.

The story goes on to describe many more events and is the beginnings of the Arthur tale as we know it today. Although some of the characters and facts were added later, Geoffrey’s account lays the foundations. However, he is not a historian and his work has been refuted on many occasions.

Unlike in previous accounts, Geoffrey does not look upon Arthur as a mere warrior. He is described as if he were a Messiah, a topic expanded upon by Barber (1972) in his chapter "The National Messiah".

Geoffrey does refer to historical people, however, and then does give some indication of date. For example, he mentions the Roman Emperor Leo, which is generally held to be Leo I (457-474)

Geoffrey also places Arthur in Gaul and says that this was likely the place of his death. Perhaps the idea of Avalon, the place Arthur was taken when wounded, could echo with the real place "Avallon" in Burgundy in Gaul.

We are reminded of Riothamus, who campaigned in Gaul at the time in question. It was believed that his name was Arthur. Geoffrey uses this idea in his account and,, indeed, many of the facts concerning Riothamus echo with what little we ‘think we may’ know of Arthur. It would seem that this Riothamus is the only documented person who has any connection with the Arthurian stories.

This is where Geoffrey’s Arthur differs from those of other writers because one could say that his Arthur was a fantasy but that there had once been a true Arthur or Riothamus who proved to be a base for his character.

It was perhaps with Merlin that Geoffrey added his own touch to the Arthur story in that he was Geoffrey’s creation. In truth, Geoffrey used the name from a Cumbrian seer named Myrddin. He latinised the name to Merlin. He gave Merlin the credit for Arthur’s birth and the building of Stonehenge, as well as accrediting him with magical powers.

The first mention of Morgen le Fay is from Geoffrey although she has not yet become the nefarious character that we may think of today.

Merlin was later to be exaggerated by romancers in later years. He became a central figure in the story and was given various attributes including that he was a devil’s son, he arranged Arthur’s birth and helped in his rise to power, he helped acquire Excalibur for Arthur and prepared him for his quest for the Holy Grail.

It was after Geoffrey that these additions were made by various writers which all contributed to the legend as we know it today. It was soon after that the early prose versions of the Arthur story were written. These texts can then be counted as literary texts.