Quote Originally Posted by Pharnakes
Why would he gat the fist born trait?

You ony get that when you are the first born, I don't see what relevance that has here.
Amusingly he was not the firstborn son, but I guess because he has the trait because he has "comes after his father" and - other than his brother who is dull/languorous etc - is sharp/charismatic/vigorous and has made a career from the beginning. And I have never seen firstborn before, so I thought it could be related to the fact that in his case his father has pushed his career by being famous and that everybody sees him as his fathers younger double.