Sinhalese kingdom centered at Anuradhapura in Sri Lanka and its capital from the time of the introduction of Buddhism in the 3rd century BC until the site was abandoned in the 10th century AD after many incursions by the Tamils of South India. The South Indians gained control of the kingdom several times - in the 2nd, 5th, and again in the late 10th century AD, after which Anuradhapura was finally abandoned as the Sinhalese capital in favor of Polonnaruva. There was also internal warring by clans trying to establish separate dynastic lines. The most important Anuradhapuran dynasties were the Vijayan (3rd century BC-1st century AD) and the Lamakanna (1st-4th century AD and 7th-10th century). Buddhist monuments include palaces, monasteries, and stupas, many of which have been conserved and restored. During its 1,000 years of existence, the kingdom of Anuradhapura developed a high degree of culture. Among the most famous are the Thuparama stupa, the Ruvanveli dagaba (an enormous stupa), and the Lohapassada monastery. The kingdom also developed a remarkably complex system of irrigation, considered by many scholars to be its major achievement.