What is "kahavanu"

Kahavanu is a medieval currency from Sri Lanka.

This anonymous gold coinage appears to have been initiated shortly before Rajaraja Chola invaded Lanka in 990 AD, and struck through the period when the Cholas dominated the island (1017-1070), and continued by closely similar coins struck for Vijayabahu (1055-1110) after he re-established Sinhala independence in 1070. Like other Lankan coins from around 11th Century no date is indicated. It is not certain whether the Kahavanu was introduced at Ruhuna, the region in the south of the island to which the Sinhala court had been obliged to move as a result of Rajaraja's conquests.