Kassapa is the name of a Buddha, the third of the five Buddhas of the present aeon (the Bhaddakappa or 'Fortunate Aeon'), and the sixth of the six Buddhas prior to the historical Buddha mentioned in the earlier parts of the Pali Canon(D.ii.7). In the Buddhist texts in Sanskrit, this Buddha is known as Kāśyapa.
Kassapa was born in Varanasi, in the Deer Park at Isipatana, India for his Brahmin parents Brahmadatta and Dhanavatī, of the Kassapagotta. Kassapa lived for two thousand years in the household in three different palaces. They are Hamsa, Yasa and Sirinanda. (The BuA.217 calls the first two palaces Hamsavā and Yasavā). His chief wife was Sunandā and had a son called Vijitasena. Kassapa gave up his worldly life traveling in his palace (pāsāda). He practiced austerities for only seven days. Just before attaining enlightenment he had accepted a meal of milk-rice from his wife and grass for his seat from a yavapālaka named Soma. His bodhi (the tree under which he attained enlightenment) was a banyan-tree and he preached his first sermon at Isipatana to an assembly of monks who had renounced the world in his company. Kassapa performed the twin miracle at the foot of an asana-tree outside Sundaranagara. He held only one assembly of his disciples; among his most famous conversions was that of a yakkha, Naradeva (q.v.). His chief disciples were Tissa and Bhāradvāja among monks, and Anulā and Uruvelā among nuns, his constant attendant being Sabbamitta. Among his patrons, the most eminent were Sumangala and Ghattīkāra, Vijitasenā and Bhaddā. His body was twenty cubits high. Kassapa dies at the age of forty thousand years, in the Setavya pleasance at Setavyā in Kāsī. Over his relics was raised a thūpa one league in height, each brick of which was worth one crore.
There has been a great dissimilarity of opinion on what should be the size of the stupa and using what material it should be built. These points have been finally settled and the work of building was started. But then the citizens found they had not enough money to complete the thupa. In order to find this money, an anāgāmī devotee, named Sorata, went all over Jambudīpa, requesting the help of the people for the completion of the thūpa. He sent the money as he received it, and on hearing that the work was completed, he set out to go and worship the thūpa; but he was seized by robbers and killed in the forest, which later came to be known as the Andhavana. Upavāna, in a previous birth, became the guardian deity of the chetiya, hence his great majesty in his last life (DA.ii.580; for another story of the building of the shrine see DhA.iii.29). Among the thirty-seven goddesses noticed by Guttila, when he visited heaven, was one who had offered a scented five-spray at the chetiya (J.ii.256). So did Alāta offer āneja-flowers and obtain a happy rebirth (J.vi.227). The cause of Mahā-Kaccāna's golden complexion was his gift of a golden brick to the building of Kassapa's shrine (AA.i.116). At the same chetiya, Anuruddha, who was then a householder in Benares, offered butter and molasses in bowls of brass, which were placed without any interval around the chetiya (AA.i.105).
Since there is no archeological evidence for the existence of Kassapa, he is placed in the Legendary figures category. But for Theravada Buddhists and most other Buddhists, Kassapa was a real person who became a Buddha.