What is "dipavamsa"

The Dipavamsa or Deepavamsa (i.e., "Chronicle of the Island"; in Pali: Dīpavaṃsa), is the oldest historical record of Sri Lanka. It means Chronicle of the Island. The chronicle is believed to be compiled from Atthakatha and other sources around the 3-4th century. Together with the Mahavamsa, it is the source of many accounts of ancient history of Sri Lanka and India. Its importance resides not only as a source of history and legend, but also as an important early work in Buddhist and Pali literature.