An Arahant, celebrated for his discussions with King Milinda. He was the son of the Brahmin Soṇuttara, in the village of Kajaṅgala in the Himavā.

He was well versed in the Vedas, and entered the Order under Rohaṇa to learn the Buddha’s teaching. Later he went to Assagutta of the Vattaniya senāsana and studied under him. There, one day, at the conclusion of a meal, while giving thanks to a lay woman who had looked after Assagutta for more than thirty years, Nāgasena became a Stream-winner. Then he was sent to Pāṭaliputta, where he studied under Dhammarakkhita, and there he attained Arahantship. Subsequently he went to the Saṅkheyya pariveṇa in Sagala, where he met Milinda.

It is said that in his previous birth he was a deva, named Mahāsena, living in Tāvatiṃsa, in a palace called Ketumatī, and that he consented to be born among men at the insistent request of Sakka and the Arahants led by Assagutta.

In an earlier life he had made an aspiration to be able to defeat Milinda in discussion.

For further details see Milindapañha, 6 ff.