Parākramabāhu I (S1123–1186) is king of Sri Lanka from 1153 to 1186.
During his reign from his capital Polonnaruwa, he unifies the three sub kingdoms of the island, becoming one of the last monarchs in Sri Lankan history to do so.
He oversees the expansion and beautification of his capital, constructs extensive irrigation systems, reorganizes the country's army, reforms Buddhist practices, encourages the arts and undertakes military campaigns in southern India and in Myanmar.
Parākramabāhu spends much of his youth in the courts of his uncles Kitti Sri Megha and Sri Vallabha, the kings of the principalities of Dakkhinadesa and Ruhuna respectively, as well as in the court of the King of Rajarata, Gajabahu II.
He succeeds his uncle Kitti as king of Dakkhinadesa around 1140 and over the next decade improves both Dakkhinadesa's infrastructure and military.
Following a protracted civil war, he secures power over the entire island around 1153 and remains in this position until his death in 1186.
During Parākramabāhu's reign, he launches a punitive campaign against the kings of Myanmar, aids the Pandyas against the Chola Empire in southern India and maintains extensive trade relations with China and countries in the Middle East.
Within the island, he consecrates religious monuments, builds hospitals, social welfare units, canals and large reservoirs.