Robin Hood and the Potter is Child ballad 121, and among the oldest existing tales of Robin Hood.
The device of disguising himself as a potter may have been taken from the older legends of Hereward the Wake.
Robin Hood demands a toll of a potter. They fight, and the potter wins. Robin Hood buys his pots and trades clothing with him, then makes his way into Nottingham to sell the pots. He charges ridiculously low prices and so sells them all. He meets with the sheriff, shows him how he can shoot, and tells him that he knows Robin Hood. The sheriff asks him to lead him to the outlaw. Robin agrees, and the sheriff is surrounded by Robin's men in Sherwood. Because of hospitality of the sheriff's wife in Nottingham, Robin lets him go free.
This is the oldest existing instance of a motif to be common in latter ballads: Robin Hood meets his match. No more than that is the plot of Robin Hood and the Tanner and Robin Hood and the Ranger, and it is an element of Robin Hood and the Tinker.