took the lead in reform movements. As the new Mahāvihāra Theravāda school became dominant in Sri Lanka, it gradually spread through mainland Southeast Asia. Theravāda established itself in Myanmar in the late 11th century, in Thailand in the 13th and early 14th centuries, and in Cambodia and Laos by the end of the 14th century. Although Mahavihara never completely replaced other schools in Southeast Asia, it received special favour at most royal courts. This is due to the support it received from local elites, who exerted a very strong religious and social influence. Fragmentation and decline After the death of Parākramabāhu I, his realm disintegrated into warring factions, and South Indian invaders resumed their attacks on the island, eventually leading to the swift decline of the Polonnaruva kingdom. There was a brief period of rebuilding under Nissanka Malla, who promoted the building of great Buddhist centres at Nissanka Latha Mandapaya, Rankoth Vihara and Hatadage. However, the kingdom continued to decline, under the attacks by South Indian states. The last Sinhala king to rule from Polonnaruva was Parākramabāhu III (1302–1310), who was actually a client king of the Pandyas and later had to retreat to Dambadeniya. After this, Sinhala kings were forced to retreat further to the south (to cities like Kurunagala and Gampola), mainly in search of security from South Indian states and from the expansive Tamil kingdom of Jaffna (a Hindu realm which now controlled the north-west of the island). This instability also led to the decline of the discipline of the Sangha. Sinhala kings tried various measures to stem this decline, such as purging the sangha of undisciplined monks and introducing the post of sangharaja (chief of the sangha) under the Gampola kings. Regarding sectarian differences, these had mostly been worked out at this point in time, with the adoption of some Mahayana (as well as Hindu) deities and the rituals of the other sects into the Theravada orthodoxy. The cult of the tooth relic retained its importance for example. In spite of all the instability, Sri Lanka was seen by Buddhists in Southeast Asia as a new holy land, since it contained relics of the Buddha which were accessible, in contrast to India which had seen the disappearance of Buddhism and the Muslim invasions. This period of the Dambadeniya kings also saw a flowering of religious poetry, such as the Kavsilumina, written by the king Parākramabāhu II