Parakrama Bahu I (päräk`rəmə bä`ro͞o), fl. 12th cent., Sinhalese king of Ceylon (now Sri Lanka; 1153–86). He was the first to unite the island under one rule after Chola invaders were driven out in the late 11th cent. He made his capital at Pollonarrua, which became a great cultural center, and encouraged the construction of a highly efficient irrigation system that helped to make the island prosperous. After securing his hold on Ceylon, he invaded S India and sailed to Myanmar with an army.