According to the most widely accepted version of its origin, the Ayutthaya Kingdom rose from the earlier, nearby Lavo Kingdom and Suvarnabhumi with Uthong as its first king. Ayutthaya was a patchwork of self-governing principalities and tributary provinces owing allegiance to the King of Ayutthaya under the mandala system. Its initial expansion was through conquest and political marriage. Before the end of the 15th century, Ayutthaya invaded the Khmer Empire three times and sacked its capital Angkor. Ayutthaya then became a regional power in place of the Khmer. Constant interference of Sukhothai effectively made it a vassal state of Ayutthaya and it was finally incorporated into the kingdom. Borommatrailokkanat brought about bureaucratic reforms which lasted into the 20th century and created a system of social hierarchy called ''sakdina'', where male commoners were conscripted as corvée labourers for six months a year. Ayutthaya was interested in the Malay peninsula, but failed to conquer the Malacca Sultanate which was supported by the Chinese Ming Dynasty.