Parakramabahu I

Parakramabahu I (1123–1186 AD) was a medieval Sri Lankan king who ruled from Polonnaruwa and is remembered as one of the greatest monarchs in Sri Lankan history. He is best known for his famous declaration: 'Let not even a drop of water that comes from the rain flow into the ocean without being made useful to man.' Under his rule, Sri Lanka experienced a golden age of hydraulic engineering, with the construction of massive irrigation tanks and canals that transformed the dry zone into a prosperous agricultural region. He also unified Sri Lanka under a single administration and conducted military campaigns in South India. His reign is considered the peak of medieval Sinhalese civilization.