Complex sentence: The Academy was founded in 1856, by the Sisters of Saint Joseph at the request of the Bishop of Brooklyn, Mother Austin Kean came from Philadelphia to Brooklyn to found what is now the Sisters of St. Joseph of Brentwood, New York.
Split into simpler sentences: The Academy was founded in 1856, by the Sisters of Saint Joseph. At the request of the Bishop of Brooklyn, Mother Austin Kean came from Philadelphia to Brooklyn to found what is now the Sisters of St. Joseph of Brentwood, New York.