a Pandyan prince. Polonnaruwa period During the Middle Ages Sri Lanka was well known for its agricultural prosperity under king Parakramabahu in Polonnaruwa during which period the island was famous around the world as the rice mill of the east. Transitional period Later in the 13th century the country's administrative provinces were divided into independent kingdoms and chieftaincies: Kingdom of Sitawaka, Kingdom of Kotte, Jaffna Kingdom and the Kandyan kingdom. The invasion by the Hindu king Magha in the 13th century led to migrations by the Buddhists (mostly Sinhalese) to areas not under his control. This migration was followed by a period of conflict among the Sinhalese chiefs who tried to exert political supremacy. Parakramabahu VI, a Sinhalese king invaded the Jaffna Kingdom and conquered it, bringing the entire country back under the Sinhalese kingdom for 17 years. Trade also increased during this period, as Sri Lanka began to trade cinnamon and a large number of Muslim traders were bought into the island. In the 15th century a Kandyan Kingdom formed which divided the Sinhalese politically into low-country and up-country. In this period, the Sinhalese caste structure absorbed recent Dravidian Hindu immigrants from South India leading to the emergence of three new Sinhalese caste groups - the Salagama, the Durava and the Karava. Modern history The Sinhalese have a stable birth rate and a population that has been growing at a slow pace relative to India and other Asian countries. Society Demographics Sri Lanka Within Sri Lanka the majority of the Sinhalese reside in the South, Central, Sabaragamuwa and Western parts of the country. This coincides with the largest Sinhalese populations areas in Sri Lanka. Cities with more than 90% Sinhalese population include Hambantota, Galle, Gampaha, Kurunegala, Monaragala, Anuradhapura and Polonnaruwa. Diaspora Sinhalese people have emigrated out to many countries for a variety of reasons. The larger diaspora communities are situated in the United Kingdom, Australia, United States and Canada among others. In addition to this there are many Sinhalese, who reside in the Middle East, Southeast Asia and Europe, temporarily in connection with employment and/or education. They are often employed as guest workers in the Middle East and professionals in the other regions. The largest population centres of the Sinhalese diaspora are mainly situated in Europe, North America and Australia. The city of Melbourne contains just under half of the Sri Lankan Australians. The 2011 census recorded 86,412 Sri