Helots were Messenian servants who lived in Sparta after Sparta took over their homeland. They had very little rights and were treated as servants, though they are not considered common slaves...
the helots were captive works from ancient Greece. this name comes from the Greek word for "capture". but I'm not sure the answer to the second question. sorry:(
Deometras of Sparta (former king) claimed their was 8000 full citizens during the greco-Persian wars during the 480bc to xerxex and plataea a spartan had 7 helots. so i am guessing 56000?