How many copies did the book, written in 1877 by the author with close historical links to the Sewell Barn Theatre, sell?
Sewell Barn Theatre: Sewell Barn Theatre is located in the grounds of Sewell Park Academy (formerly the Blyth school, later the Blyth-Jex school and Sewell Park College) on Constitution Hill in Norwich, England. Sewell Barn Theatre:  It is home to a popular amateur theatre company, with close historical links to the author Anna Sewell who wrote "Black Beauty". Black Beauty: Black Beauty is an 1877 novel by English author Anna Sewell.
i don't know