The family tree of the House of Constantine, come from three early sources:-

• Geoffrey of Monmouth ("Historia regum Britanniae", 1137),
• Wace ("Roman de Brut", 1155), and
• Layamon ("Brut", c. 1200).

Geoffrey's Historia was written in Latin, but the names I had used are the popular English.

The last two sources are adaptations of Geoffrey's Historia, where Wace wrote in French and Layamon in English.

Note that the early tradition of Arthur, there was no Lancelot, Perceval, and many others found in later Arthurian tradition.

Here, Arthur had a full sister name, Anna, which is different to most Arthurian literature. There is no Morgan le Fay, mentioned here. And also, Gawain and Mordred are brothers, and they are nephews of Arthur.

Since, Vortigern and Hengist played important roles, before Arthur's time, I had constructed a family tree for the two protagonists.

The family tree shows the family of Vortigern, and that of the Saxon leaders. The same sources were used from the previous family tree: Geoffrey, Wace and Layamon.

The family tree of King Arthur shown here, come from Chretien de Troyes' five Arthurian romances. Chretien was the first to introduce Lancelot and Perceval into the legend. He was also responsible for beginning the Grail legend.

Chretien de Troyes was more interested in the adventure of the individual hero, where Arthur played only minor role, and there was no last battle, therefore, there was no Mordred. Of all the knights, only Gawain appeared in all Chretien's romances, yet his role is minor to the hero of each romance (eg. Erec, Cligés, Yvain, Lancelot, Perceval), except in Conte du Graal. But even in Conte du Graal, Gawain does appeared in the tale, until halfway through the poem, Perceval figured largely in the first half.

Here, Morgan le Fay is Arthur's full sister. He had another unnamed sister in Conte du Graal ("Story of the Grail" or "Perceval". But if we followed the First Grail Continuation, then her name was either Norcadet or Morgawse. Also, Chretien had listed three brothers to Gawain, but no Mordred.

Another thing I should point out, is that in later literature, Morgan le Fay was the wife of King Urien and mother of the hero, Yvain. In Chretien's materials, there was no indication of Morgan's relationship with Urien or Yvain (compare it with Vulgate family tree or Malory's version).

The main sources here come from a number of 13th century romances of the Vulgate Cycle and the Post-Vulgate Cycle. Note that this is the revised (expanded) version of the previous tree of the Vulgate.

It's almost identical to the next family tree, which used Sir Thomas Malory's work, called Le Morte d'Arthur, 1469. The difference is mainly in the spelling of Arthur's nephews and the number of his sisters.

Speaking of daughters of Igraine (Ygraine), there are some confusion over their number, particularly in the Vulgate Merlin (c. 1240), where it contradict itself. There are two main texts (manuscripts) that were used to translate Merlin: Micha and Sommer.

In chapter 4, Micha text only mentioned Arthur having two half-sisters, the youngest being Morgan, while the eldest wasn't named, but traditionally the wife of King Lot was known as Morgause or Morgawse. But in the same chapter of the Sommer text, he introduced a third daughter of Igraine, who would become the wife of Neutres and mother of Galeschin.

Later, in chapter 5, Igraine's daughters had increased to five – two from her (unnamed) husband and three from the Duke of Tintagel (who was later named as Duke Hoel in chapter 9, but other sources called Igraine's husband, Gorlois). That's mean Igraine had married 3 times. The eldest (Morgause) was married to Lot and mother of 5 sons. The second married King Neutres of Garlot; she was named Blasine (Elaine) in chapter 9. The third was wife of Urien and mother of Yvain; her name, Brimesent, which doesn't appeared until chapter 19. The 4th was unnamed, and she was wife of Caradoc and mother of King Aguisant of Scotland. The 5th was in school, and she was most likely to be Morgan le Fay, since chapter 4 mentioned her learning all sort of arts in the nunnery.

Another confusion appeared because Morgan appeared as the wife of Urien and mother of Yvain, in the Post-Vulgate Suite du Merlin (Merlin Continuation). So Morgan replaced Brimesent (chapter 19 of Vulgate Merlin) in the Post-Vulgate and the tree concerning the family of Urien and Morgan would look like this:

It is different from the previous family tree based on Chretien de Troyes' Arthurian romances, showing that Morgawse and Morgan le Fay as Arthur's half-sisters.

I had used a popular Middle English work by Sir Thomas Malory, called Le Morte d'Arthur (1469), to draw up this family tree. It is almost identical to that of the French romances Vulgate Cycle and Post-Vulgate Cycle. The main difference is the names of some of Arthur's nephews were spelt different from the French romances and he had less half-sisters (only 3, in this work).