A Case of Liberation...Not only does it appear that they preserved a sense of their common history and destiny, revolting against Spartan control on more than one occasion, but they did eventually recover their freedom (if with help from other Greek states). In July 371 B.C. a battle was fought which irrevocably altered the relationship of Sparta and Messenia. In Boeotia, on the plain of Leuktra, troops led by the Theban general Epaminondas soundly defeated the Spartan forces -- their first major defeat in open combat for some three centuries. In the following year, Epaminondas invaded Sparta's home territory, at which point many Messenians rose up in revolt against their overlords. Their rejection of Spartan domination was sealed by Epaminondas' liberation of the Messenians and his foundation of the polis (city-state) of Messene on the slopes of a prominent local landmark, Mount Ithome.
University of Cincinnati
It may have been built for the Spartans, but the work was done by the helots (Messinians).