The sons promised and as soon as their father had died they began looking for the treasure. They worked very hard in the hot sun. Soon they had dug up every inch of the vineyard and all the time as they were working they wondered what their father had left for them. In their minds they pictured boxes of gold coins, diamond necklaces and other such things. But they found not a single penny. They were very upset. They felt that all their hard work had been for nothing. But when the grapes started to appear on the vines and their grapes were the biggest and best in the neighbourhood, and they sold them for a lot of money.
Now they understood what their father had left for them and they lived happily and wealthily ever after.
(This story is one of Aesop´s fables.)