sentences:  He remained at the firm for some time living in the family of his uncle, Maj.-Gen. John E. Wool there after engaging in business for himself in banking and iron works creating at the time, one of the largest and most successful establishments in the United States, known as the Albany and Rensselaer Iron and Steel Works, located in Troy.In 1857, Griswold became a large owner of the iron mills of Troy having been granted the U.S. Bessemer steel process patents important for expanding the Rensselaer Iron and Steel Works business.During the early part of the Civil War, Griswold built at his personal expense the first iron-clad Ericsson warship, the "USS Monitor" to combat the confederate converted frigate the "Merrimac", which was subsequently defeated by the "Monitor" in a historic naval battle in 1862.