People have raised sheep since very ancient times for their wool. Most clothing that the Greeks and Romans wore was made out of wool, even though wool is a very heavy fabric and southern Europe can be a very hot place to live. It is possible that itchiness was what really drove the Romans to conquer most of the known world–they may have figured that some country out there had a more breathable cloth that chaffed less.
Sheep were typically sent out to feed in the pasture. Unfortunately, sheep are highly edible. Fortunately, a shepherd would follow the sheep to ensure that wolves and similar ravenous monsters did not drag them off for a woolly evening snack. But unfortunately, as everyone knows, it is hard to stay awake when counting sheep. So, sheep had a reputation for being helpless victims, and shepherds’ for being lazy bums.