The importance of the Arabs as traders in the Indian Ocean by the 12th century may partly explain why the last Buddhist king of Maldives Dhovemi converted to Islam in the year 1153 (or 1193, for certain copper plate grants give a later date). The king thereupon adopted the Muslim title and name (in Arabic) of Sultan (besides the old Dhivehi title of Maha Radun or Ras Kilege or Rasgefānu) Muhammad ibn Abdullah, initiating a series of six Islamic dynasties consisting of eighty-four sultans and sultanas that lasted until 1932 when the sultanate became elective.The formal title of the Sultan up to 1965 was, Sultan of Land and Sea, Lord of the twelve-thousand islands and Sultan of the Maldives which came with the style Highness. The person traditionally deemed responsible for this conversion was a Sunni Muslim visitor named Abu al-Barakat Yusuf al-Barbari.