> Also, when you use compound pulley systems, you can reduce your weight by 50%, but you double your time because you have to pull double the rope distance.

You are absolutely right. What the hell was I thinking. When I was writing that statement, I was asking myself, is that correct? Thank you for setting me straight.

Now then, do you really feel it would be marginal, to reduce the amount of men needed to pull up 2 stones (5,000lbs) from 100 men, down to 50? But again, I digress, as 
this would give them technology they may have not possessed.. I have found 1 relic, if used properly, would provide block and tackle.
 
If this relic was turned upside down, and enclosed between two like pieces of wood, and the rope was greased, you would have 1/2 of a block and tackle system.