from the second half of Chapter 33 from the Great Chronicle Mahavamsa:
"A commander of troops named Kammaharattaka, overpowered the ruler, king Khallata Naga, in the capital itself. But the king's younger brother named Vatta Gamani killed the villainous commander and took on himself the government. The little son of his brother, king Khallatanaga, whose name was Mahaculika, he took as his son; and the (child's) mother, Anuladevi, he made his queen. Since he had thus taken the place of a father they called him Pitiraja.
all Sri Lanka blog articles
by region, by topic
and A-Z here...