Little Dorrit (1857) centres around the Dorrit family. William Dorrit is a long-term inmate of the Marshalsea prison for debtors (where Dickens's own father spent some time). He derives comfort from the presence of his daughter Amy, 'Little Dorrit', who was born in the prison. It is unexpectedly discovered that William is heir to a fortune, and, with the notable exception of Amy, the family becomes arrogant and purse-proud as a consequence. As paupers, Old Dorrit and Amy were befriended by Arthus Clenman; when Clenman in his turn is imprisoned for debt Amy looks after him. Yet wealth presents a consistent obstacle to their union. Clenman's family history is also the key to an elaborate mystery in which the Dorrits are involved.