Sinhalese kingdom that flourished in Ceylon (Sri Lanka) during the 15th century. Its king, Parākramabāhu VI (1412–67), was the last native sovereign to unify all of Ceylon under one rule. By 1450, Parākramabāhu VI had, with his conquest of the kingdom of Jaffna in northern Ceylon, unified all of Ceylon. By 1477, however, 10 years after the death of Parākramabāhu VI, both Jaffna and the other powerful kingdom, Kandy, had thrown off the suzerainty of Kotte. In 1505, with the arrival of the Portuguese, the king of Kotte agreed to pay tribute to Portugal, thus becoming the first Sinhalese king to accept the suzerainty of a European king. The kingdom of Kotte continued to exist nominally until 1597, when—with the death of its last ruler, Don Juan Dharmapāla—sovereignty officially passed to the king of Portugal, by a written agreement between Portuguese officials and native Sinhalese chiefs at the Convention of Malvana.