According to many historians, the root cause of ethnic strife and "ketuanan Melayu" was a lack of mixing between the Malays and non-Malays. An exception to this were the Straits Chinese, who managed to assimilate reasonably well, despite the assimilation taking 600 years including intermarriage. According to the Ming Shi-lu, the ancestors of the Straits Chinese were "gifts" given to the Sultan of Malacca as a recognition of both bilateral ties between the Ming Dynasty and the sultanate, and of Malay sovereignty. At the time, most were rich merchants during British rule instead of manual labourers and many habitually spoke Malay, dressed in the Malay style, and preferred Malay cuisine.