Jain and Buddhist sources show that the principle of nonviolence toward animals was an established rule in both religions as early as the 6th century BCE. The Jain concept, which is particularly strict, may be even older. Parshva, the earliest Jain leader (Tirthankara) whom modern historians consider to be a historical figure, lived in the 8th or 7th century BCE. He is said to have preached nonviolence no less radically than it was practiced in the Jain community in the times of Mahavira (6th century BCE). Between 4th and 1st centuries BCE, or perhaps as late as 5th century CE, ancient Indian philosopher Valluvar wrote an exclusive chapter on veganism or moral vegetarianism in his work Tirukkural, emphasizing unambiguously on non-animal diet (Chapter 26), non-harming (Chapter 32), and non-killing (Chapter 33).