Who does Johnny claim to be related to? How does he know this is true?

Johnny claims to be related to the Lytes. When Mr. Lyte laughs at Johnny and insults his mother.... he tries to send him away. Johnny, however, carefully describes the cup that his mother left him to prove that he is related to the Lytes. Mr. Lyte and his servant, Sewall, both recognize the cup from Johnny’s description. Mr. Lyte then tells Johnny he can come back at suppertime and that he should bring the cup.