Yellow Ajah History

So I can't find any sort of history for the Yellow Ajah.  I wanted to give some depth to the Ajah's history so I wanted to see if there was anything in particular that the Yellow Ajah had been a part of that you would like to add to the history.    I'd also like to create a timeline for the Ajah Heads that we have recently had.  The only things I have to add to the timeline currently are:

The Yellow Ajah has had three of it’s members raised to the Amyrlin Seat.

Catala Lucanvalle (197-223 NE)

Alvera Ramosanya (549-578 NE)

Marasale Jureen (705-732 NE)

Most recent Ajah Heads were:

Lwena: 913-970

Cavana: 970-998

Elizabeth: 998-999

What do you guys think of the dates for the past Ajah Heads?  I don't know that Elizabeth was ever played out, and because of the inactivity of the character I figured a short time as Head before she retired from it?  Perhaps at her age the stress of the position became too much and she had to retire?  I don't want to kill the character off or do anything that is detrimental to her character in case Christine decides to come back and play her, but we do need to find a legitimate reason to get her out of Ajah Head.  Or perhaps she resigns, leaves the Tower, and if Christine comes back, we can leave her to come up with reasons why, or simply let Elizabeth be aloof about why she left :P  Anyone else have thoughts on this?

Also, i'll be creating an NSW HoA since I don't feel Zalena is old enough or the type to get into a position of authority :P  I'll have her up in the next day or so for you to look at.  I have some ideas and I think you might like them Nyn... how would you like an Ajah Head for a semi-spy for the CotL??

Let me know what you guys think about it all!