In Jain tradition, there is no fixed Gregorian birth year for Rishabhanatha (Adinath), the first Tirthankara. He is described as having lived in the very ancient Krita (Satya) Yuga—millions of years ago—long before the timeline of historical BCE/CE dates. Both major Jain traditions (Digambara and Śvetāmbara) regard him as the first Tirthankara, but there are minor differences in details about his life, not in the basic fact that his birth year is not dated in modern numerical years.

If you’d like, I can share a brief synthesis of how each tradition portrays his life and where the differences lie.