I read somewhere that the great Shrines, Basilicas and Cathedrals of Europe were the first huge, monumental structures in the world which were built without slave labor.
It was free men. Paid, free labor.
Some of it freely volunteered for devotional reasons, but most of it professional, skilled artisans.
Even if the guys who did nothing but carry buckets of bricks were unskilled "peasants," they were paid.