Hello

I read this:
http://en.wikipedia.org/wiki/Gaudapada

http://en.wikipedia.org/wiki/Narayana

( He is considered to be the 1st Acharya of the Advaita school of thought as Adi Shankaracharya mentions in his text & works.[1]

http://en.wikipedia.org/wiki/Advaita_Guru_Parampara




Why is not Lord Siva the first acharya of the Advaita Vedanta?
And Lord Narayana is a central figure in dvaita vedanta bhakti school, so why the bhaktas worship the first acharya of advaita vedanta but the bhaktas don't learn advaita Vedanta?


thank you