The Esala Poya is in the month of Esala according to the Sinhala calendar and the Gregorian calendar in which we use it as July.
Several important things happened on the Esala Poya or Esala Full Moon day.
The conception of Prince Siddhartha (Bodhisattva) in Queen Mahamaya Devi’s womb occurred on this day.
Prince, Siddhartha and Princess Yasodhara’s son, Prince Rahula was born on an Esala Poya day
On this same day Prince Siddhartha gave up his lay life, donned the robes of an ascetic and went in search of Enlightenment or Buddhahood as he became disillusioned with lay life after encountering an old man, a sick man and a corpse. He realised everyone including himself a prince must go through old age, sickness and death. His final encounter was with a sadhu and he thought of becoming an ascetic or sadhu and finding the truth was the way out of Samsara (life).
Prince Siddhartha’s giving up of lay life is known as the Great Renunciation. In preparation to leave the palace he quietly went and saw his son Prince Rahula, born that day and Princess Yasodhara, his wife, both of whom were fast asleep. Then he mounted his horse Kantaka and with his trusted Minister left the Palace and his life as a Prince forever. When they came to the banks of the river Neranjana, Prince Siddhartha dismounted. He cut off his hair with his sword, took off his royal garments and donned the yellow robes of an ascetic. He gave his clothes to weeping Channa and bade him go back to the Palace and break the news of his Renunciation. The horse Kantaka watched his beloved master walk away and died of a broken heart.
After achieving Buddhahood the Buddha preached his first sermon, the Dammachakkapavattana Sutta to five ascetics, on an Esala Poya day at the Deer Park in Isipatana (present Saranath) in India. They were with him for sometime during his search for the truth.
Their names were Kondanna, Bhaddiya, Vappa, Mahanama and Assaji. At the end of the sermon the ascetics embraced Buddhism and became the first theras in the Sasana. The ascetic Kondanna attained the state of Sotapatti. Many Devas and Brahmas also listened to this first sermon.
It was on Esala Poya that the Buddha visited the Tauvthisa Dev Lova, (Tauvtisa abode of the Gods) and for the first time preached the Abidhamma to the Maathru Divya Rajaya (who was Mahamaya Devi in her previous birth) and the other Gods there.
The Buddha performed the Yamaka Maha Prathiharya or the Twin Miracles on an Esala Poya Day to show that He was the Buddha to the proud, older Sakya clansmen. He rose into the air and walked over and he made flames come out of the upper part of his body and water from the lower part. Then he reversed the process. Then, the Buddha made fire come out of the right side of his body and water from the left side of his body. He also emitted six resplendent rays of light from his body.
For Sri Lankan Buddhist the Esala Poya is very important as several important events took place on Esala Poya day.
The first ordination of a Sri Lankan took place on an Esala Poya day in Anuradhapura. Prince Ariththa, nephew of King Devanampiyatissa was ordained as a bhikkhu by Arahath Mahinda.
It was on an Esala Poya day that the laying of the foundation for the Ruwanvelisaya took place and the enshrinement of relics by King Dutugemunu.
Esala Poya also marks the start of the Vas Kalaya (rainy season retreat) for bhikkhus. Vas commences on the day after the Esala Poya. Bhikkhus who were not able to start Vas on this day will be allowed to start late Vas on the next poya day which is Nikkini Poya, the poya day in the month of August.
It was on an Esala Poya Day that the Sacred Tooth Relic was brought to Sri Lanka by Princess Hemamala and Prince Dantha. Dante Pura, (City of the Tooth) in the state of Kalinga, on the Eastern coastal belt of India (present Orissa) was the home of the Sacred Tooth Relic originally.
The then King of Kalinga, Guhasiva was a devout Buddhist. His greatly feared that the Hindu kings would try to destroy the Sacred Tooth Relic. Therefore, he instructed his daughter, Princess Hemamala and her husband Prince Danta took to bring the Sacred Tooth Relic to Sri Lanka where it would be safe with the King of Sri Lanka who too was a devout Buddhist.
Princess Hemamala disguised herself as an ordinary woman and hid the Sacred Tooth Relic in her hair. They left the port Tamalitti, Kalinga and sailed to Lanka and landed at Lankapattana. From here they walked to Anuradhpura and handed over the Sacred Tooth Relic to King Kithsirimevan (AD 303-331).
The King, who was also known as Kirthi Sri Meghavarna was very happy to receive the Sacred Tooth Relic and kept it for a few days in a monastery, called Meghagiri, the present Isurumuni Viharaya. Subsequently, the Sacred Tooth Relic was deposited in a building called Dhamma Cakka Geha built by King Devanampiyatissa.
The Sacred Tooth Relic was taken annually to Abhayagiri Viharaya in a grand procession and kept there for three months.
It is thought that this procession could be the origin of today’s annual Esala Dalada Perahera held in Kandy and associated with the Dalada Maligawa. The Perahera is held in August.