Polonnaruwa which served as the capital for three centuries is the next great ancient sites of Sri Lanka after Anuradhpura. Although the sites are more than 1000 years old,are generally in better repair than the sites that of Anuradhpura. The Singhalese kings moved the capital from Anuradhpura to Polonnaruwa as it was more defendable against the invading South Indains but Polonnaruwa also fell to the invading South Indian Chola dynasty in the 10th century. But the invaders were driven out of the islan in 1070 by Sinhalese king Vijayabahu –I and kept Polonnaruwaas the capital. But it was under king Parakramababu (r 1153-86) that Polonnaruwa reached its zenith. It was a period when master plans were drawn, huge buildings were erected and large scale irrigation was achieved with the construction of a massive 2500-hectare tank. But the long term survival of Polonnaruwa as a capital proved difficult as it was susceptible to south Indian invasions.