Robert Franklin Brattan was born on May 13, 1845, in Barren Creek Springs in
Somerset (now
Wicomico) County,
Maryland to Elizabeth (née Venables) and Joseph Brattan. His father was a merchant and agriculturist. His grandfather was
Joshua Brattan, a state delegate from Somerset County. Brattan was named for his uncle, Franklin Brattan, a lawyer who practiced law with
David Davis in Illinois. At the age of nineteen, during the
American Civil War, Brattan was arrested on a charge of carrying a Southern spy near his home. His father was also arrested on charges of disloyalty. Brattan attended schools in Somerset County. He graduated from
Washington College of
Chestertown, Maryland, in 1864. Brattan was appointed as deputy register of wills for Somerset County. He served in that role from September 1864 to March 1867. Brattan read law with the firm Jones & Irving, working with
Isaac D. Jones and
Levin Irving. He was
admitted to the bar in July 1867. He continued with the firm Jones & Irving until January 1868. ==Career==