Sri Lankan’s were transformed culturally, socially and intellectually with the introduction of buddhism to Sri Lanka by Arahant Mihindu in 236 B.E. (Circa 250 B.C.)  under the patronage of Emperor Asoka (268-239 BC)  (Eggermont, 1956) also known as Dharmasoka (Gombrige,1988, pg 127- 136). Even long before Buddhism was formally introduced to Sri lanka, the natives had a fair knowledge and practised buddhism. The evidence for this fact can be traced by Buddhagosha thero’s “Samantha pasadika” and in ancient chronicles as “Deepawansa” and “Mahawansa” (The History of Ceylon(University Press), Vol I, Parts I & II). Lord Buddha himself visited Sri Lanka three times and the people would embrace buddhism wholeheartedly due to it’s compassionate nature, non discriminatory attitude and benevolence. Also the close proximity to India and commercial ties via trade accelerated the process but with the arrival of Arahant Mihindu Buddhism became the religion of the nation.
The paper analyse the change in Sri Lankan society which was more transformational than evolutionary. Buddhism became the catalyst for a better change which reflected novel and humanistic approach to every day lives and enriched the culture, ethics and society at large.
This relic was also enshrined within the same stupa, which was enlarged to a height of 18 feet (5.5 m). The same Sri Lankan Sources can be attributed for the validity by referring to the parallel passages in,i. the Dipavamsa (4th Century A.C.);ii. the Mahavamsa (5th Century A.C.);iii. the Samanthapasadika, the commentary to the Vinaya Pitaka by Acharya Buddhagosha (5th Century A.C.);iv. the Vamsatthappakasini, the commentary to the Mahavamsa. (9th Century A.C.);
and relating to the Indian sources such as the,i. the rock edicts of Asoka -Bhabru Edict (Dhamma refers to Buddha Dharma)ii. the Asokavadana (2nd Century A.C.); 
Third Buddhist Council and dissemination of Dhamma.
The third buddhist council under the patronage of King Asoka was primarily to cleanse the Buddhist religion (Sasana) from vast numbers who joined sasana with ulterior motives for personal gains. During this council under the leadership of Moggaliputta Tissa there, the pali cannon of the Theravada was finally redacted. At this council was slo taken the modt important decision to sustain the Dhamma by sending missionaries to different regions to preach Buddhism and establish sasana there. Arahant Moggaliputta Tissa thero instructed Ven. Majjhantika to kasmira – gandhara, Ven. Mahadeva to mahisamandala, Ven Rakkhita to Vanavasi and Ven. Mahinda Thero with Iththiya, Uttiya, Sambala and Bhaddasala to Sri Lanka. The instructions for the delegate to Sri lanka, “Establish ye in the delightful land of lanka the delightful religion of the Vanquisher”  (Perera,1998, pg 12.). Arahant Mihindu was the son of emperor Asoka. It is important to note that with Arahant Mihindu there are 4 other arahants accompanying a lay person to visit Sri Lanka.
Buddhist mission to Sri Lanka
Arahant Mahinda adopted the religious life at the age of twenty and under the guidance of many learned buddhist monks mastered the doctrines and attained the highest spiritual life – the Arahatship. At that time the king of Sri Lanka was “Mutasiva” and Arahant Mahinda perceived due to his old age it was advisable to wait until Mutasiva’s son become the ruler.
Devanampiya Tissa was the second son of Mutasiva, also was a friend of Emperor Asoka. The first thing he did when he became the King was to sent emissaries to India. When they returned, they delivered the following message;
“Aham Buddhan ca Dhamman ca Sanghan ca
Upasakattam vedesim Sakyaputassa sasane
tvamp’imani ratanani uttamani naruttama cittam
pasadayitvana saddhaya saranam bhaja”
“I have taken refuge in the Buddha, his Doctrine and his order,
I have declared myself a lay-disciple in the religion of the Sakya son; seek
then, O best of men, refuge in these best of gems,
Converting your mind with believing heart”
Therefore before encountering Arahant Mihindu, King Devanampiya Tissa understood and knew about the Buddha dhamma. The first meeting of the King of Lanka and Arahant Mihindu was graphically and eloquently described in the chronicles of Sri Lanka. During a hunting expedition with his men king saw the arahat bhikku’s with shaven heads dressed in yellow robes, of dignified men with distinguished appearance, who faced him and addressed him not as ordinary men addressing a king but as those to whom a king was their inferior. (Perera,1988) The conversation impressed the king, Arahant Mahinda in replying to the king’s questions explained the following,
“ Samana mayam Maharaja Dhammarajassa savaka
tav’eva anukampaya jambudipa idhagata”
“We are the disciples of the Lord of the Dhamma.
In compassion towards you, Maharaja,
We have come here from India”
Then arahant Mihindu conversed with the king and realised the king was intelligent enough to comprehend dhamma. Arahant Mihindu preached the Chulahatthipadopama sutra . After listening to the sermon and listening to Buddha dhamma by kings friend’s (Asoka) own son would have elated the king thus the king and his forty thousand entourage became disciples of Buddha. Even the sermons by arahant Mihindu were intended to arouse the critical analytical faculties of the people and to iterate them the foundations of buddhism, such as reasoning, non-duality and clearly buddhism is not a set of dogmas set down by authoritarian ruler nor an arrogant declaration of one’s own opinion. Instead Buddhism was considerate to aid the lay person as well as the Sangha in spiritual, intellectual and societal manner. The king invited the sangha for alms at the palace when leaving Mihintale mountain.
Discourses for the Lankan Society
Arahant Mahinda arrived on Anuraphapura the capital city, on the invitation of the King for alms. After the alms giving ceremony Arahant Mahinda preached the Petavatthu, the Vimanavatthu and Sacca-samyutta for the Royal household. These sermons explains the suffering of the petha’s in lower realms and delights of the Deva’s in Vimana’s (higher realms) due tot heir own good and bad karma (Good and bad deeds). Due to the sheer demand from the people arahant Mihindu preached at the elephant stables. On this occasion arahant Mihindu preached Devaduta Sutta (Majjhima Nikaya, No.130) Due to the increase of people more seats were provided at Kings Garden and arahant Mahinda preached Balapanditha Sutta, (Majjhima Nikaya, No.129) When the arahant revealed their desire to retreat to Mihinatale, King granted the royal park and for the sangha to stay in the capital.
Progress Of Buddhist Dhamma in Sri lanka
Buddhism was introduced to Sri lanka during the first year of King Devanampiya Tissa’s reign, He ruled the country for Forty years and buddhism progressed in Sri lanka in leaps and bounds. The king worked zealously for the progress of Buddhism. The king established Mahavihara, Chetiyapabbata vihara, Thuparama Maha Vihara and the Sacred Bo tree and remains so this day. The chronicles further elaborates the creation of Isurumuni- Vihara, Vessagiri Vihara and the construction of Pathmaka pagoda and Jambukola vihara along with other many parks and centres for the use of monks. Hundreds and thousands of men and women joined the new bhikkhu community and king graciously provided the requisites for the monks.
Further to strengthen it more arahant Mihindu asked king to ordain a person born to Sri Lankan parents and the king obliged by ordaining Ariththa, the kings nephew. Ariththa became a monk along with five hundred others and became enlightened arahats.
Women Disciples and the Sacred Bodhi Tree
Women held a very high status in society during this period. In every strata of society the position of women showed no distinction from that of men. Thus women in Sri Lanka desires to be the disciples of buddha and the dialogue was headed by queen Anula, King sent emissaries to India and delighted emperor Asoka send Ven. Sangamitta to Sri Lanka. Ven. Sangamitta was the sister of Mahinda Thero. Emperor Asoka was so delighted as a token of appreciation planted a branch of Sacred Bo Tree in a golden vessel and sent it to Sri Lanka with ve. Sangamitta. Along with the Sacred Bo tree emperor Asoka dispatched large number of attendants to accompany the Bo tree. According to the chronicles this entourage consisted of 64 families, selected from brahmins, nobles and householders. The ship sailed from Tamralipti (Tamluk) and arrived at “Jambukola” port (Modern day located as the cove west of Chillaalai and adjacent to the northwest tip located about 20 km from Jaffna town and 10 km from Kankasanthurai) in Sri Lanka in seven days. The sacred Bo Tree was planted in Mahamegha garden of Anuradhapura with great festivities and with great respect.
The remarkable success of arahant Mihindu’s mission and rapid spread of the religion in a very short time was mainly attributable to the mammoth efforts of arahant Mihindu and unbounded patronage of King Devanampiya Tissa. Many contributing factors supported this effort, mainly the people from Sri lanka were intellectually and emotionally ripe at this period to perceive and adopt the teachings of buddha dhamma. The country was without any external or internal aggressions, the people in the land were prosperous with very few needs and wants. They were contended with what they had and without any anger, animosity or malice towards none. With a fertile soil and timely rain blessed them with abundance of free time after the harvests. They used these free time to engage, discuss and practice buddha dhamma. It was like a rain on fertile soil, dhamma was a blessing to these people with intellectual curiosity and benevolent demeanour. Hundreds of thousands of men hearing the new massage and thus the law of the Blessed One was firmly established.
Kings demise and passing away of Ven. Mahinda and Ven.Sangamitta.
After the demise of King Devanampiya tissa his brother King Uttiya became the successor. Arahant Mihindu lived to the age of 80 years and Ven. Sangamitta to the age of 79 years. They spent nearly 48 years in the island. Arahant Mihindu died in the eighth year of the reign of king Uttiya and Ven. Sangamitta in the ninth year of King Uttiya’s reign. The king performed the funerals with great honour , devotion and built stupas over the relics. The king himself died in the following year, 286 B.E, after reign of ten years . The firm establishment of monastic order in Sri Lanka was evident as the hierarchy of disciples was continued after the passing away of arahant Mihindu. It was continued in pupillary succession as ben Aritta succeeded arahat Mihindu, then was succeeded by Isidatta, Kala-Sumana, Dighanama and Dighasumana theros.
The “Rasavahini” a pali work composed in the 13th Century contains over a hundred stories of the life of the people during the early period. There were no caste discrimination nor divisions according to the vocation in Sri Lanka. The religion of the natives alias sinhalese during the period was purely and entirely Buddhist and the stories indicate much practical activity in religious affairs, both in endowment and maintenance of religious institutions and the practice of religious principles. The canonical scriptures are not being committed to writing at this time and writing was unknown to the island nation The monks learned the dhamma and preserved the tradition by way of reciting and frequent preaching and teaching. The monks were the teachers, instructors and counsellors of the people. The dhamma was expounded on every occasion and sermons to large congregations were given in the temples. Once a year a seven day discourse on “Ariyawansa Deshana” sermon was done in temples and people gathered in hundreds and thousands to listen to the sermon. The way of preserving dhamma was instructed by Buddha were to, recite. “Theravada” Buddhist tradition was established in Sri Lanka and according to the traditions and various customs laid in various parts of the Tripitaka were learned by the monks thus committed to memory and preserved in oral tradition.
The social and cultural development in the Sinhalese community during the two centuries following their acceptance of Buddhist teachings were clearly displayed by the advancement of their literature, arts, societal norms and even dress codes. The piety, charity and benevolence were prominent with their dealings with each other and even foreigners. With the introduction of buddhism Sri Lanka became the new spiritual power house to disseminate and preserve the buddha teachings thus the tradition has been continued for the last 2300 years, proclaiming the Buddha’s wise words that “In this Country (Sri Lanka) my teachings will be preserved for 2500 years”