who were direct descendants of immigrants from Chittagong district [Bengal]" in the 20th-century, states historian Aye Chan. Kingdom of Mrauk U The Rakhines were one of the tribes of the Burmese Pyu city-states. The Rakhines began migrating to Arakan through the Arakan Mountains in the 9th century. The Rakhines established numerous cities in the valley of the Lemro River. These included Sambawak I, Pyinsa, Parein, Hkrit, Sambawak II, Myohaung, Toungoo and Launggret. Burmese forces invaded the Rakhine cities in 1406. The Burmese invasion forced Rakhine rulers to seek help and refuge from neighbouring Bengal in the north. Early evidence of Bengali Muslim settlements in Arakan date back to the time of Min Saw Mon (1430–34) of the Kingdom of Mrauk U. After 24 years of exile in Bengal, he regained control of the Arakanese throne in 1430 with military assistance from the Bengal Sultanate. The Bengalis who came with him formed their own settlements in the region. The Santikan Mosque built in the 1430s, features a court which "measures from north to south and from east to west; the shrine is a rectangular structure measuring ." King Min Saw Mon ceded some territory to the Sultan of Bengal and recognised his sovereignty over the areas. In recognition of his kingdom's vassal status, the Buddhist kings of Arakan received Islamic titles and used the Bengali gold dinar within the kingdom. Min Saw Mon minted his own coins with the Burmese alphabet on one side and the Persian alphabet on the other. Arakan's vassalage to Bengal was brief. After Sultan Jalaluddin Muhammad Shah's death in 1433, Narameikhla's successors invaded Bengal and occupied Ramu in 1437 and Chittagong in 1459. Arakan would hold Chittagong until 1666. Even after independence from the Sultans of Bengal, the Arakanese kings continued the custom of maintaining Muslim titles. The Buddhist kings compared themselves to Sultans and fashioned themselves after Mughal rulers. They also continued to employ Muslims in prestigious positions within the royal administration. Some of them worked as Bengali, Persian and Arabic scribes in the Arakanese courts, which, despite remaining Buddhist, adopted Islamic fashions from the neighbouring Bengal Sultanate. The population increased in the 17th century, as slaves were brought in by Arakanese raiders and Portuguese settlers following raids into Bengal. Slaves included members of the Mughal nobility. A notable royal slave was Alaol, a renowned poet in the Arakanese court. The slave population were employed