when did jainism started?

Jainism as a living tradition is ancient and traceable to many Tirthankaras beyond history. The historical grounding usually given is that the 24th Tirthankara, Mahavira (Vardhamana), lived around the 6th century BCE.

• Common approximate dates: Mahavira’s life is often placed around 599–527 BCE.
• What “started” means: In Jain tradition, the Jain path (Dharma) is eternal and has always existed in some form; the organized teaching and public preaching began with Mahavira and earlier Tirthankaras are believed to have taught in different eras.
• Important caveat: Exact dates are debated. Some scholars could give slightly different ranges, but the general consensus centers Mahavira in the 6th century BCE.

Different Jain sects (Digambara and Śvetāmbara) both acknowledge Mahavira as the last Tirthankara in this cycle, though they may differ on some details of chronology and interpretation.