Râjagaha, the capital of the kingdom of Magadha, was one of the first places visited by the Buddha soon after his enlightenment. As a wandering ascetic in the early days of his renunciation, he had promised King Seniya Bimbisâra that he would visit Râjagaha when he achieved the object of his search. King Bimbisâra was overjoyed at the sight of the Buddha, and having listened to his teaching, became a lay follower. His devotion to the Buddha became so ardent that within a few days he offered him his pleasure park, Veluvana, for residence.
Râjagaha during that time was a centre of great learning where many schools of philosophy flourished. One such school of thought had as its head Sañjaya; and among his retinue of two hundred and fifty followers were Upatissa and Kolita, who were later to become Sariputta and Mahâ Moggallâna, the two chief disciples of the Buddha.
One day when Upatissa was walking through the streets of Râjagaha, he was greatly struck by the serene countenance and the quiet, dignified deportment of one of the first disciples of the Buddha, the arahat Assaji, who was on his alms round.
All the strenuous endeavours to achieve perfection that Upatissa had made through many a birth were now on the verge of being rewarded. Without going back to his teacher, he followed the arahat Assaji to his resting place, eager to know whom he followed and what teaching he had accepted.
"Friend," said Upatissa, "serene is your countenance, clear and radiant is your glance. Who persuaded you to renounce the world? Who is your teacher? What Dhamma (teaching) do you follow?" The Venerable Assaji, rather reluctant to speak much, humbly said: "I cannot expound the Doctrine and Discipline at length, but I can tell you the meaning briefly." Upatissa’s reply is interesting: "Well, friend, tell little or much; what I want is just the meaning. Why speak many words?" Then the arahat Assaji uttered a single verse which embraces the Buddha’s entire doctrine of causality:
Upatissa instantly grasped the meaning and attained the first stage of realization, comprehending "whatever is of the nature of arising, all that is of the nature of ceasing" (yam kiñci samudayadhammam sabbam tam nirodhadhammam).
With a heart full of joy, he quickly went back to his friend Kolita and told him of his meeting with the arahat and of the teaching he had received. Kolita, too, like Upatissa, instantly gained the first stage of realization, having heard the Dhamma from his friend. Thereon both of them approached Sañjaya and asked him to follow the Buddha. But afraid of losing his reputation as a religious teacher, he refused to do so. Upatissa and Kolita then left Sañjaya,much against his protestations,for the Veluvana monastery and expressed their wish to become followers of the Buddha. The Buddha gladly welcomed them saying, "Come, monks, well proclaimed is the Dhamma. Live the holy life for the complete ending of suffering." He admitted them into the Order. They attained deliverance and became the two chief disciples.
Another great one who joined the Order during the Buddha’s stay at Veluvana was the brahmin sage Mahâ Kassapa, who had renounced great wealth to find the way to deliverance. It was the Venerable Mahâ Kassapa, three months after the Buddha’s passing away (parinibbâna), who called up the convocation of arahats (the First Council), at the Sattapanni Cave near Râjagaha under the patronage of King Ajâtasattu, to collect and codify the Dhamma and Vinaya.