Do not think that the Buddha appeared as fungi appear in the field after the autumn rain. The Gotama Buddha is one more of a list, not very long, of Sammasambuddhas who had the mission of making the Dhamma known to the human beings of his generation.
If it is still unclear how this transmission is made, it is done in two ways, the direct or brahminical way in which one of the highest brahmās, who were anagamis produced by a past Buddha, makes the Dhamma known to a man , not a woman (and do not get angry with women) who will later give in to the pressure of this same Brahma and make it known, which is the case of the Sammasambuddhas, or not. If he does not give up, he stays in Paccekabuddha, or solitary buddha from whom there will be no news.
The second way, the indirect, the Sammasambuddha, unique in his generation, gathers an open group of people to whom he reveals that same Dhamma. From this group will arise the nobles or ariyas, the most relevant being the arahants, but also people who will not go overboard.
As we saw, it was the Brahmā Sahampati who tutored the Buddha and also convinced him to teach.
Sahampati was an anagami named Sahaka in the noble Sangha of the Buddha Kassapa, just prior to the Gotama.
32. The Speech of Āṭānāṭiya
The Seven Buddhas
«May you reverence Vipassī,
the glorious Visionary,
than reverent to Sikhī,
that has mercy on all beings.
«May you revere Vessabhū,
the austere, purified (of the corruptions),
you can revere Kakusandha,
that has crushed Māra’s army.
«How reverent to Koṇāgamana,
the consummate brahmin,
that you reverence Kassapa,
which is free in all aspects.
«May you revere Aṅgīrasa,
the glorious son of the Sakyans, the
who preached this Dhamma,
which is the dissipation of all suffering.
«Those who are emancipated in the world,
that have a perception (in things) as they are,
those people free of malicious language,
that are large and fully mature,
«They will venerate Gotama,
which is of benefit to gods and men,
who has understanding and good conduct,
which is large and completely mature.
A Buddha of the past, whose story is told in the Mahæpadāna Sutta. He was born in Khema Park in Bandhumatī, his father is Bandhmatā and his mother Bandhumatī. It belonged to Koṇḍañña gotta. He preached his first sermon at Khemamigadāya to his half-brother Khandha and the son of his purohita, Tissa; These two later became his main disciples. His constant assistant was Asoka; Caṇḍā and Candamittā were his main disciples. His main lay patrons were Punabbasummitta and Nāga among men, and Sirimā and Uttarā among women. DN.ii.2 ff.
A Buddha of a past age. DN.ii.7 DN.iii.195 f. SN.ii.9
He was born in the pleasure of Nisabha in Aruṇavatī.
His father was the Khattiya Aruṇa and his mother Pabhāvatī.
His wife was Sabbakāmā and his son Atula.
His Bodhi was a puṇḍarīka.
The Bodhisatta was Arindama, king of Paribhutta.
Abhibhū and Sambhava were his main disciples among the monks.
Akhila and Padumā among the nuns.
His constant assistant was Khemaṅkara.
Among its sponsors were Sirivaḍḍha and Canda among men,
and Cittā and Suguttā among women.
King of Avanti in the time of Reṇu. Its capital was Māhissatī. DN.ii.236
A Buddha of a bygone era. His main disciples were Vidhura and Sañjiva among the monks, and Sama and Campá among the nuns. His personal assistant was Buddhija. Accuta and Samaṇa, Nandā and Sunandā were his most eminent lay supporters. DN.ii.7 In the time of Kakusandha, a Māra, called Dūsī (a previous birth of Moggallāna), caused many problems for the Buddha and his followers, largely treating the Buddha’s patience. MN.i.333 ff. Thag.1187 The Saṃyutta Nikāya SN.ii.190 f. he mentions that during the time of Kakusandha, Mount Vepulla of Rājagaha was called Pacina-vaṃsa and the inhabitants were called Tivarā.
The second Buddha was born in the Bhaddakappa. He was a brahman of the Kassapa clan who lived for 30,000 years. His tree of illumination was an Udumbara, his two main disciples were Bhiyyosa and Uttara, and he had an assembly of 30,000 monks, all arahants. His assistant was Sotthija, his father was Yaññadatta, his mother was Uttarā, and the king at that time was Sobha, who lived in the capital of Sobhavatī. DN.ii.1
In the time of Koṇāgamana, Mount Vepulla was known as Vaṅkaka, and the people who lived on the mountain were called Rohitassā, whose life span was thirty thousand years. SN.ii.191
One of the seven Buddhas mentioned in the Canon. DN.ii.7
Among those who attained the status of Arahans under Kassapa is mentioned Gavesī, who, with his five hundred followers, always strived to excel to achieve his goal. AN.iii.214 ff.
During the time of the Buddha Kassapa, the Bodhisatta was a young brahmin named Jotipāla who, later, under the influence of Ghaṭīkāra, became a monk. DN.ii.7 DN.iii.196 This Ghaṭīkāra was born later in the world of Brahma and visited Gotama, after his Enlightenment. Gotama then reminded him of this past friendship, that Ghaṭīkāra seemed too modest to mention. SN.i.34 f.