The Il Full Moon Poya is very important in the Buddhist calendar.
A number of significant events in connection with the Buddha's life occurred on this Poya day.
It was on Il Full Moon Poya Day that the Sakyamuni Gautama Buddha sat under the Bo tree and delivered His first sermon – the Dhamma Chakka Pawaththana Sutta.
Sixty Arahaths, the five Ascetics - Kondangna, Vappa, Baddiya, Assaji and Mahanama- and Yasa and his 54 friends were there to listen to the sermon.
The Dhamma sermon contained the essentials of the Buddha's teachings- the Four Noble Truths and the Noble Eightfold Path.
After addressing the Arahaths, the Buddha said, “Go forth, O Bhikkhus, for the welfare of the many, for the happiness of the many, out of compassion for the world, for the good, benefit and happiness of gods and men, and preached the doctrine of Dhamma to all for their well-being.