During the Buddha's stay near Rajagaha, there was a well-known teacher of one of the traditional schools. He had about two hundred students, and among them were Upatissa and Kolita. These two students were best friends. They wanted to learn more about life and death, than what their teacher taught them. So they agreed between themselves that they would search for the highest knowledge, and as soon as one of them found it, he would share it with the other.