[drieddust]

> India as a whole didn't even exist back then...

Vishnu Puran composed circa 400 BCE to 900 CE says.

  उत्तरं यत् समुद्रस्य हिमाद्रेश्चैव दक्षिणम् | वर्षं तद् भारतं नाम भारती यत्र सन्ततिः ||

 Land that lies north to the sea and south of Himalaya is called Bharat(India) and it's people Bharti (Indian)

Political system was diffrent from what we see today. But that doesn't mean land called Bharat didn't exist culturally and politically.