Gajabahu I of Anuradhapura
Gajabahu I (lit. 'Elephant-Arm'), also known as Gajabahuka Gamani (c. 113 – 135 CE), was a Sinhalese king of Rajarata in Sri Lanka. He is renowned for his religious benefactions, extensive involvement in south Indian politics, and for possibly introducing the cult of the goddess Pattini to Sri Lanka. The primary source for his reign is the Mahavamsa, though he is also the only early Sri Lankan king (along with Elara) to be extensively mentioned in the Chera Cilappatikaram (also spelled Silapathikaram).
Next to nothing is known about Gajabahu's youth, except that he was son of Vankanasika Tissa (reigned 110-113), king of Rajarata from Anuradhapura, and his consort Mahamatta. As such he must have witnessed the most dramatic event of Tissa's reign, the invasion of Rajarata by the Chola king Karikalan 
The Mahavamsa mentions Gajabahu's accession and reign of twenty-two years, and mentions neither Karikalan's invasion, nor the military campaigns to south India that Gajabahu became famous for. Instead he is presented as a great patron of religion; the chronicle credits him with the construction of two viharas - Matuvihara and Rumika - and a stupa called Abhayuttara. He is also credited with making a mantle for Dutugemunu's Mirisavetiya, and for building a reservoir to provide the Abhayagiri monastery with food. He also made improvements to the four entranceways of the Abhayagiri stupa.
Gajabahu is also credited with the introduction of the cult of the goddess Pattini to Sri Lanka. The Silapathikaram mentions Gajabahu's presence at the consecration of a temple to Kannagi (identified as Pattini in this case) by the Chera king Senguvuttan. Returning from India he brought back not only the begging bowl of the Buddha but Pattini's sacred anklet, and constructed a temple to the goddess 'at a place called Vattapalli near Mullaitivu'. However, there is an alternative view that the cult actually arrived in Sri Lanka in the 13th century, and the legend of Gajabahu's patronage was retrospectively created to generate legitimacy for the goddess 
The annual Perahara held in Kandy is also thought to have its roots in Gajabahu's reign. Following the successful completion of a campaign into Chola territories the temple of Vishnu in Anuradhapura is said to have staged a procession in thanks, which eventually developed into today's festival.
In contrast the mentions of Gajabahu in the Tamil sources represent a much more cordial visit by the Sri Lankan king. The Silapathikaram mentions him twice. On the first occasion he is with the Chera king Senguvuttan, offering sacrifices to the goddess Kannagi in an introductory passage. Later he is in the Chera king's company again, and on very good terms.
It has been suggested that this mention does not necessarily preclude a military campaign; after all it is entirely possible that Gajabahu and Senguvuttan offered joint sacrifices as a way of securing a freshly concluded peace. On the other hand, the versions presented in the Mahavamsa and Silapathikaram do not mention any violence at all, despite being the major sources for this period. Furthermore, the reliability of the entires in the Silapathikaram has been questioned, and it has been suggested that the meeting between Gajabahu and Senguvttan is the result of a certain amounth of 'poetic licence' on the part of the compiler 
Sources notwithstanding, Gajabahu is regarded in modern Sri Lanka as an archetype of the mighty Sinhalese monarch. The Sri Lanka Army has an infantry regiment, Gajaba Regiment, named after the warrior king, and the Sri Lanka Navy had named a ship named after the king, the SLNS Gajabahu.
It is also possible to argue that Cheran Senkuttuvan's father Cheran Kutako Nedum Cheral Athan and uncle Cholan Karikal Valavan jointly attacked the northern part of Lanka from Vedaranyam in Tamil Nadu, India and in the process Cheran Nedum Cheral Athan managed to cut down the protector tree of Sinhaleese king of the time, which has the name 'Kadampu' as stated in Sangam literature (Pathittupathu 2.10). The Sinhaleese king (probably the father of Gajabahu) was ruling from Anuradhapura, which was washed by the River Kadamba, the present Malwatu Oya. The protector tree was replanted by the mother of Gajabahu in their palace garden. Probably there was a truce between Gajabahu and the Cheras and the hostages were exchanged as a mark of friendship. If this was not the case Gajabahu would not have visited Cheran Senkuttuvan, for a ceremony highly objected to by the Pandian King, since Pandian kingdom was an immediate neighbour of Gajabahu's kingdom.
There have been a series of archaeological excavations in recent years at the ancient port Godavaya (= Godawaya, Gothapabbata), situated around a huge rock overlooking the Indian Ocean, close to the gem mining area of the Lower Sitracala Wewa and the inland shipping route of the Walawe Ganga. The archaeologists have found that Godavaya's was an important stop on the maritime Silk Route, in the early centuries of the Common era with excavations and research revealing connections from China to the Red Sea and the Mediterranean. A stone inscription in Brahmi, dating to Gajabahu I's reign, orders that part of the customs collections at the Godavaya Port at Ambalanthota be donated to the nearby Godapawath Temple. There have been three inscriptions and some 75,000 late Roman coins found in earthen vessels in the region.