Apparently the Adi Shankara founded the
Sringeri Mathain Karnataka in the ninth
century A.D. He had constructed there an
altar on which he placed a sitting form of
Saraswati, the Goddess of Knowledge and
Learning.
From what I've read, the Adi had brought
the Saraswati idol from Kashmere. The form
of Saraswati is in a sitting position with a
Sri Yantra in one hand, a book in the other.
With Her two other arms, the She is
depicted playing a Vina, and making the
auspicious hand sign with the other.
The Auspicious Handsign:
http://rwilliams.us/archives/brahmanand.htm
The Adi placed the Sri Yantra in the hand of
the Sarasawti, upon which he had inscribed
the bija mantra of Saraswati.
Swami Krishnananda Saraswati:
http://rwilliams.us/archives/srividya.htm
The Adi then composed the Saunaryalahari
for our understandiing.
In the Saunda, the Adi included fifteen bija
mantras, and then he added a sixteenth. as
fertilizer for the other fifteen. The sixteenth bija
is the TM bija mantra given out by the Mahesh
Yogi.
These are the bija mantras that are used by
all the Saraswati sannyasins that follow the
Adi Shankaracharya and the Shankara Advaita
Tradition. All the proponents of the tradition have
the surname of Saraswati. For example, Swami
Brahmanand Saraswati.
Swami Brahmanand Saraswati:
http://rwilliams.us/archives/guiding_light.htm
Twice daily they meditate using the bija mantras
that they were given by their teacher. All of the
Saraswati sannyasins meditate on the Saraswati
bija mantra. The Saraswati sannyasins follow the
Sri Vidya tradition, 'vidya' meaning knowledge and
'sri' means the female personification of the
Godhead, i.e. a Tantric sect.
Our tradition begins with the Adi Shankara
through our Guru Dev, whose teacher was
Swami Krishnananda of Uttar Kashi all the
way back to Gaudapapda, the teacher of
Shankara.s teacher, Govindacharya.
Gaudapadacharya:
http://rwilliams.us/archives/mandukhya.htm