Lerna I and II - Neolithic occupation. The site seems to have been deserted for a time before re-occupation.
Lerna III - settlement was surrownded with a double ring of defense walls with gates and towers and a number of solid buildings within. Destroyed by fire.
Lerna IV - Early Helladic III period. settled by new inhabitants - destroyers of Lerna III?
Lerna V - continues throughout the Middle Helladic period.
See:
- N. G. L. Hammond, Tumulus-Burial in: The Annual of the British School at Athens, Vol. 62 (1967), pp. 77-105
- http://www.perseus.tufts.edu/hopper/artifact?name=Lerna&object=Site&redirect=true