जैन धर्म के प्रारंभिक धार्मिक ग्रन्थों और आगमों की रचना मुख्य रूप से किस भाषा में की गई थी?

In Ancient Indian Statecraft, Kautilya's 'Rajamandala' theory primarily deals with:

The First Buddhist Council was held at ______.

Which ancient Indian text contains references indicating that population counts or census-like records were maintained in ancient India?