Upvote:1
The History of the Bhikkhuni Sangha by Dr. Chatsumarn Kabilsingh (as well as another like it by Dhammananda bhikkhuni) says that their presence at the first council wasn't recorded (what was recorded was the council's making Ananda apologize for introducing women into the sangha).
It also says,
I have doubts that only men-five hundred male arhats-were at this council. On uposatha days every new and full moon, the bhikkhunis would recite their Patimokkha Sutta apart from the monks. I believe that technically, it could not be possible for the monks to recite the Patimokkha Sutta of the nuns, and so bhikkhunis must have been present at the First Council. The recorders, who were all monks, may not have thought it important to mention their presence. Some monks have been kind enough to speak about this point: recently, a Sri Lankan monk told me that he too did not think that only men attended the First Council.
The official account says "no".
Upvote:2
The Ariyas are "breast born" sons and daughters of the Buddha and they sometimes address each other as elder brother or sister as a mark of respect, according to their accomplishments.
Given that it is a council of Arahants, would it even occur to them to notice that there is a distinction, even in terms of class or sex amongst them, and that distinction is marked enough to make a separate representative body, which participation somehow adds or detracts something on the authority of the council?
The council of Arahants would look more suspicious if it was thought that some of those distinctions were relevant and recorded.
The patimokkha is different, in that, later it was made up of ariyas and putthujannas and the rules of the women were slightly different and more than the men.