|A Dance with Dragons (mentioned)
Hop-Bean's father sold him to a slaver when he was three, but he grew up to be such a famous mummer that he was able to buy his freedom. He traveled to all of the Free Cities, and Westeros as well. He acquired the name Hop-Bean in Oldtown.
At some point he met Penny and Oppo's mother, who was a normal sized person. It was his idea to do the dog and pig tilts. He trained the first pig but by then he was too sick to ride her, so Oppo took his place. Penny always rode the dog. Hop-Bean also taught his children to beware "big people", to act ever complacient and funny to them.
A Dance with Dragons
Penny tells Tyrion Lannister of her father and that he bought his freedom. Tyrion is not impressed. On the auction block outside Meereen Tyrion is angry that Penny's mouth is frozen in a rictus of a smile. "Well trained for your amusement", Tyrion thinks. He thinks to himself that her father had a deal to answer for, in whatever small hell was reserved for dwarfs.
You have to be careful around big people. Be jolly and playful with them, keep them smiling, make them laugh, that's what my father always said.