Which Tirthankara attained enlightenment under a banyan tree?

Which Tirthankara attained enlightenment under a banyan tree? Rishabhanatha attained kevala jnana, or omniscience, beneath a banyan tree.

Jain tradition says Rishabhanatha undertook austerities for 1,000 years after renouncing his royal life. At Purimatala, beneath the sacred banyan known as Akshayavata in some accounts, he destroyed the karmas that obscured perfect knowledge and became an omniscient Jina.

This event is distinct from nirvana. Kevala jnana is enlightenment during embodied life: the Tirthankara remains alive and teaches. Nirvana or moksha comes later, when the soul leaves the body and is permanently liberated. Rishabhanatha’s final liberation is traditionally placed at Ashtapada, identified with Mount Kailash.

Rishabhanatha is the first of Jainism’s 24 Tirthankaras, and the banyan is listed among his distinctive associations. The story is sometimes confused with other Tirthankaras’ enlightenment traditions, but the banyan-tree association in this question points to Rishabhanatha.