Nagarjuna went with the nagas (dragons) under the sea and discovered a vast treasure trove of Mahayana Sutras, among them the many versions of the Prajnaparamita Sutra. He studied them for 50 years and taught them throughout India.
"The original Prajnaparamita is the text called the Great Mother: the Prajnaparamita of 100,000 Lines. It purports to record the full audience give by Shakyamuni Buddha on Vulture Peak with the greatest explicitness and completeness ... Over the centuries various abridged versions have emerged, including the very short One Letter Sutra, (the letter A), the short Heart Sutra, the concise Diamond-cutting Sutra, the 8,000 Line, the 18,000 or 20,000 Line, andthe 25,000 Line Sutras, from a total of eighteen Sutras. These are all considered the same Sutra, differing only in length and detail, never in basic import...
"These perfect wisdom texts served as the foundation for a systematic curriculum developed over many centuries in the Mahayana Buddhist monastic universities, among the earliest universities on this planet... This ancient curriculum opend the minds of millions of practictioners for a thousand years in India. Around 1000 C.E., it was transferred to the Tibetan monastic universities and six hundred years later to the Mongolian institutions, wherein it has flourished until the present day. The recent destruction of Mongolian and Tibetan civilizations by Russian and Chines communist invasions has severely restricted the number of practitioners who have access to the curriculum. About fifteen thousand Tibetan monks in monastic universities rebuilt in India and the Himilayan countries are the last practitioners of this transformative spiritual curriculum of Prajnaparamita education.
"In East Asia, it seems clear that Prajnapaamita served as the basis of the Ch'an and Zen traditions... The famous Sixth Patriarch of Ch'an in China, Hui Neng, recalled his own perfect wisdom upon a single hearing of the Diamond-cutting version of the Prajnaparamita." (Robert Thurman)
The Prajnaparamita Sutras are the essence of perfect wisdom and the Goddess Prajnaparamita, as the physical embodiment of perfect wisdom, is the source of highest enlightenment for all the Buddhas. She permeates all space, time, and dimensions, just as the background noise in the universe created by the Big Bang permeates all physical reality.
The Gods and Goddesses of the Buddhist pantheon create many "emanations" to serve humanity. The most profound and touching emanations are those Goddesses and enlightened humans who embody the spirit of Prajnaparamita. Tara is perhaps the greatest and certainly the most accessible of the emanations of Prajnaparamita and is likewise known as the Mother of all the Buddhas.