Okay, so ever since Morgana found out that she is Uther's daughter she has been saying that she is the rightful heir to Camelot. Well the history buff in me couldn't take anymore of that so I've compiled a list of reasons why she isn't however I am still stumped as to why Agravaine is helping Morgana. I can understand it if his vendetta is against Uther and wanting him dead is a result of him blaming Uther for Ygraine's death but that doesn't explain why he would aid Morgana against Arthur.
The Rightful Ruler of Camelot: Arthur vs. Morgana aka Reasons Why Agravaine Shouldn't be Aiding Morgana
First, we have Arthur, child of Uther and Ygraine and by birthright the
heir apparent to the throne of Camelot. In episode 1x09, Arthur "being of age and heir apparent" is crowned the
Crown Prince of Camelot.
Next, we have Morgana, child of Gorlois and Vivienne, or so we are led to believe; however in episode 3x05 we learn that Morgana is actually the illegitimate child of Uther and Vivienne.
Now from a history point of view we know that most European countries followed primogeniture, which, by law or custom, is the right of the firstborn to inherit the entirety of a parent's wealth, estate and title to the exclusion of younger siblings. We also know that the most common practice of primogeniture was
agnatic primogeniture or patrilineal primogeniture. Agnatic primogeniture is inheritance according to the seniority of birth among the sons with sons and their male issue inheriting before brothers and their issue (to the exclusion of females). Under agnatic primogeniture
male-line males inherit before females of the male line. See the
Salic Law. The Salic Law was used right through the middle ages up until at least the 15th century.
From the 15th century onwards we saw the beginnings of the
male preference primogeniture. Under the male preference primogeniture females are allowed to succeed if she has no living brothers and no deceased brothers who left surviving legitimate descendants. As we know the male preference primogeniture eventually gave way to
absolute, equal or lineal primogeniture, known as (full) cognatic primogeniture nowadays. Cognatic primogeniture, not practiced by any modern monarchy before 1980, is inheritance by the oldest surviving child regardless of gender.
It is from this that we are able to see that Arthur is the rightful ruler of Camelot. Not only was he heir apparent by birth right, but he was crowned the Crown Prince. Morgana, on the other hand, has next to no claim. She is female, the illegitimate daughter and possibly the younger sibling. Also Uther has never publicly claimed her as his own and until he does any claims she makes of being his illegitimate child are null and void. These three things come together to mean just one: she has no right of succession.
Which brings me to Agravaine.
Agravaine knows Morgana is Uther's illegitimate daughter, which means one of two things:
1) Uther and Vivienne's affair happened while Ygraine was still alive thus making Morgana older than Arthur.
2) Uther and Vivienne's affair happened after Ygraine had died thus making Arthur older.
The first scenario shows Uther betraying Ygraine while she was still alive. If this is the case why would Agravaine help the product of Uther's betrayal? He should be aiding Arthur, who along with Ygraine, are the victims of Uther.
In the second scenario we see that Morgana is the younger of the two (which means that Arthur is already the heir) and therefore has no claim to the throne. Also while Uther is not an adulterer is this scenario, Morgana is still his illegitimate daughter and gives up claim to the throne to a legitimate heir. If this is the case why would Agravaine help Morgana get the throne when it is Arthur's in every sense.
I know that liberties have been taken with history before however they can usually be overlooked. I find myself unable to do so in this situation.
Also I apologise for this, it's just that the history buff in me took over and wouldn't let me rest until I got this out.