This is part of a series of stories this year about Robert E. Lee in connection with the bicentennial of the Confederate commander's birth.

IN THE MIDDLE of Baltimore's Patapsco River, just below the Key Bridge, a small hexagonal island crouches in the shallows on the edge of Sollers Point Flats. Currently facing an uncertain future, Fort Carroll will be remembered for its association with Robert E. Lee and its fate as an island fortress besieged only by progress, politics and the creeping erosion of time.

Fort Carroll is a fortified artificial island of 3.4 acres, originally designed to shield Baltimore from a repeat of the invasion suffered during the War of 1812.

As Baltimore expanded after that war, people came to realize that Fort McHenry, the storied home of "The Star-Spangled Banner," was just too close to the city to provide adequate protection. At the urging of Col. Joseph G. Totten, then chief of the Army Corps of Engineers, Baltimoreans filed a petition to the Senate in 1841 to build a new defensive fort.

In 1847, the state of Maryland agreed to permit the U.S. War Department to site a fort seven miles downriver from the city and Fort McHenry, on the north side of the Patapsco's main channel, positioned to repulse foreign fleets trying the river route to Baltimore.

Fort Carroll was one of 50-some maritime fortresses eventually built along the Atlantic and Gulf coasts, positioned to defend major port cities. Part of the "Permanent System" or "Third System" of coastal defenses, the fortresses were the products of a military that had been forged in the War of 1812 and tempered in the Mexican War of 1846-48. Robert E. Lee was one of the more promising engineering officers to come out of that latter conflict.

After his service in Mexico, Lee returned home to Arlington at the end of June 1848, but just a few days later he was back in uniform on "special duty" in Totten's office, and by July 21 he was reinstated as a member of the board of engineers for the Atlantic Coast defenses, a position he vacated while serving in Mexico.

On Aug. 24, 1848, Lee received a brevet commission for his bravery at Chapultepec, and became Col. Lee.