been written in Sinhala Language into the Pali Language during the Anuradhapura era. When other Theravada countries such as Siam (Thailand) and Ramanna (Part of Burma/Myanmar) lost their monastic lineage, Sri Lankan monks were sent to re-establish the Upasampada monks' lineage during the period of the Polonnaruwa Kingdom in Sri Lanka. Later, in the 17th century CE, the Upasampada Lineage had disappeared in Sri Lanka due to attacks and the subsequent domination of Western intruders. A novice monk, Weliwita Saranamkara, brought Upasampada from Siam (Thailand) and was able to reestablish the lineage in Sri Lanka. During the 18th century several monks were able to again bring new Upasampada lineages from Amarapura (a part of Burma/Myanmar) and Ramanna (a part of Burma/Myanmar). Today three main Theravada Nikayas (Lineages) such as Siam Niakaya, Amarapura Nikaya, Ramanna Nikaya are dominant in Sri Lanka: Siyam Nikaya is the lineage from Siam, Amarapura Nikaya is the lineage from Amarapura and the Ramanna Nikaya is the lineage from Ramanna. Forest Traditions Forest monks and monasteries In the early days, the forest traditions were affiliated either with the Great Monastery Mahavihara in Anuradhapura or with other main ancient monasteries such as Mihintale, Ritigala, Dimbulagala, Situlpawwa. Many ruins and caves of ancient forest monasteries can be seen in the large forest areas of Anuradhapura, Polonnaruwa, Matale, Tissamaharama, Situlpawwa and Ruhuna and all over the island. Sri Lanka was then the center of Theravada Buddhism as well as the Theravada forest tradition in the world. Many stories about ancient forest monks are recorded in the Pali Atthakata and Visuddhimagga. Currently the largest forest sect in Sri Lanka is the Sri Kalyani Yogashrama Samstha (Galduva Sect) of Rāmañña Nikāya of Amarapura–Rāmañña Nikāya. In addition, several other sects such as Vaturuvila, Polgasduva continue to have several forest monasteries. Preserving Pure Upasampada The validity of upasampada (high-ordination) of the monks is considered to be weaken if the monks become less respecting towards the Vinaya (monastic discipline) and Vinaya-kammas (disciplinary procedures) in Buddhist monkhood. The ordination is considered to be invalid, if the upasampada-kamma (high-ordination procedure) was not done properly according to the texts. Ancient forest monks were considered to be well aware of this and have been protecting the validity of upasampada in the main three Theravada countries up until the period of Amarapura forest monks in Burma. During the 19th century, two groups of Sri Lankan monks were considered to be