Mahinda was the son of Emperor Ashoka. He became a Sthaviravada (Sanskrit; Pali: Theravada) monk at the age of 20 and joined the effort to spread Buddhism. Mahinda together with four other monks were sent to Sri Lanka to spread Buddhism. They preached the teachings of the Buddha to King Devanampiyatissa (247-207 BC), who then become the first Sri Lanka monarch to become a Buddhist. Mahinda brought with him the Pali Canon.
Sri Lanka is the oldest continually Buddhist country, TheravadaBuddhism being the major religion in the island since its official introduction in the 2nd century BC by VenerableMahinda, the son of the Emperor Ashoka of India during the reign of King Devanampiya- Tissa.
Arhat Mahinda, the profoundly sapient thera, came to Sri Lanka as bidden by his father, the emperor Asoka (264-267 BC) of India, who was earlier known as Chandasoka (Asoka the wicked), but later, when he renounced armed conquests, he came to be known as Dharmasoka (Asoka the pious).
However, Arhat Mahinda postponed his mission to Sri Lanka until the time was appropriate for him to undertake the mission, as the then king Mutasiva (367-307 BC), was too old and feeble to understand the doctrine of the Buddha.
The Venerable Mahadeva was sent to Mahinsakamandala (modern Mysore) and the Venerable Rakkhita Thera was dispatched to Vanavasi (northern Kanara in the south of India.) The Venerable Yonaka Dhammarakkhita Thera was sent to Upper Aparantaka (northern Gujarat, Kathiwara, Kutch and Sindh).
The VenerableMahinda Thera, The Venerable Ittiya Thera, the Venerable Uttiya Thera, the Venerable Sambala Thera and the Venerable Bhaddasala Thera were sent to Tambapanni (now Sri Lanka).
The late Venerable Mahasi Sayadaw was appointed the noble task of asking the required questions about the Dhamma of the Venerable Bhadanta Vicittasarabhivamsa who answered all of them learnedly and satisfactorily.