Well, whatever Sri Gautam Swami, the gandhar or the prime student of Lord Mahavir got from thee, he compiled it into 12 parts called as dwadas ( twelve) angas.There was also knowledge from the tradition of Pre-Lord Mahavir, that is from Lord Parshvanath's tradition and even from before that.Those were called as "Purvas".The word 'purva' itself means 'before'.In our texts there is mention of 14 purvas.
These 14 purvas are described in the 12th anga of Jinvani which is called as 'Dristivaad' anga.
Unfortunately the knowledge of these purvas was lost after Sri Bhadrabahu Acarya.It will be worth to mention that many of these purvas were dedicated to the description of the secret magical knowledge,super-natural powers ,astrology,future-telling etc apart from tattvas,dravyas and ayurved.
A story ,I had heard that Once Sri Bhadrabahuji saw a muni using these powers, and got the intuition that in the forthcoming times, this knowledge can be misused.So it is said that he didn't preached these knowledge.Sri Bhadrabahuji who was the guru of Chandragupta Maurya, was the last person to have knowledge of all these 14 purvas apart from all the other angas .After him for nearly 170 yrs the Acaryas like Vishakhacharya , Dharmsen Acarya etc were having knowledge of only the first 10 purvas.But after, this no one had knowledge of purvas.
Only Dharsen acarya who used to live in a cave in Girnarji, was having the knowledge of some chapters of the 2nd purva named as Agraayani.He taught this to two brilliant munis named as Bhutbaliji and Pushpdantji, who compiled this into granths- mostly into Sri Shatkhandaagamji.So, Shatkhandaagam is a treasure for us, it has the knowledge which came from the shraman tradition of pre-Mahavira period.The time period of compilation of Shatkhandaagam is said to be about 160 AD.
It is also worth-mentioning that some chapters of the 5th purva that is gyanpravad was known to Acarya Gundhar and on the basis of which he wrote Kashay-Pahud granth.
Now, what happened to the Angas?
Well, as per digambers the knowledge of the 11 angas was were lost and are not available and they were lost in something like within 200 yrs of the nirvana of Mahavir.But Swetamber tradition says that the 11 angas’ meaning and principles etc were preserved and were then written down by the jain monks after some 1000 yrs of nirvana of Mahavir.But digambers do not accept their authority.
What are Anga-Bahyas Agams?
These were the expanision of the angas by the srutkevalis or the monks who were having the knowledge of atleast 10 purvas.But, these srutkevalis also not found after Sri Bhadrabahuji was at the time of Chandragupta Maurya.
Now these anga-bahyas are also said to be lost by digambers.However, the swetamber do accept their exixtence.But,all the sanghas of swetambers are also not unanimous on that.Murtipujak swetambers accepts 34 anga-bahya agams while sthanakwasi and terapanthi swetambers have only 21 of these.It is said the agams which are not accepted by these latter two are related to idol-worship and related things which these sects don’t believe.
