On the Indian subcontinent, Arakan/Bengal, Malabar, and Coromandel remained the most important source of forced labour until the 1660s. Between 1626 and 1662, the Dutch exported on an average 150–400 slaves annually from the Arakan-Bengal coast. During the first thirty years of Batavia's existence, Indian and Arakanese slaves provided the main labour force of the company's Asian headquarters. Of the 211 manumitted slaves in Batavia between 1646 and 1649, 126 (59.71%) came from South Asia, including 86 (40.76%) from Bengal. Slave raids into the Bengal estuaries were conducted by joint forces of Magh pirates, and Portuguese traders (chatins) operating from Chittagong outside the jurisdiction and patronage of the Estado da India, using armed vessels (galias). These raids occurred with the active connivance of the Taung-ngu (Toungoo) rulers of Arakan. The eastward expansion of the Mughal Empire, however, completed with the conquest of Chittagong in 1666, cut off the traditional supplies from Arakan and Bengal. Until the Dutch seizure of the Portuguese settlements on the Malabar coast (1658–63), large numbers of slaves were also captured and sent from India's west coast to Batavia, Ceylon, and elsewhere. After 1663, however, the stream of forced labour from Cochin dried up to a trickle of about 50–100 and 80–120 slaves per year to Batavia and Ceylon, respectively.