In the most commonly told story the shepherd (Muhammed edh-Dhib) threw a rock into a cave in an attempt to drive out a missing animal which he was looking after. The shattering sound of pottery drew him into the cave, where he discovered several ancient jars containing scrolls wrapped up in linen.
A shepherd boy was looking for some lost goats in the hills around the Dead Sea. He came across a cave and wondered if they had fallen in there, or if anything was in there. When he dropped a stone into the cave opening he heard the sound of pottery breaking and determined to return the next day in search of 'treasure'. He came back with another boy, the rest is history of probably the greatest archaeological discovery of the 20th century.