Little Lord Fauntleroy by Frances Hodgson Burnett

In mid-1880s Brooklyn, New York, Cedric Errol lives with his Mother (never named, known only as Mrs Errol or "dearest") in genteel poverty after his Father Captain Errol dies. They receive a visit from Havisham, an English lawyer with a message from Cedric's grandfather, Lord Dorincourt. With the deaths of his father's elder brothers, Cedric is now Lord Fauntleroy and heir to the Earldom and a vast estate.