The city of New Orleans is justly famous for balcony railings, window grilles, fences, and gates. Graceful wrought-iron tracery and florid cast-iron creations are particularly noticeable in the old section of the city, the Vieux Carre. Much of this ironwork was created in the period that many consider "the classic age of southern culture," the ante-bellum South. But what few realize is that a large part of it was hammered out by black slaves.
There has been very little written on the origins of New Orleans' ironworks. The earliest theory of origin credited New Orleans' ironwork to black slaves or, more probably, free men of color. Much later, a second theory claimed that the city's early ironwork, though perhaps designed locally, was actually fabricated in the vicinity of the Spanish city of Seville. In his Fabulous New Orleans, Lyle Saxon paid this tribute to black ironworkers in his description of the old Ursuline Convent:
The staircase, which rises in a gentle curve to the second story, is particularly fine, with its balustrade of hand-hammered ironwork. Like the bolts, bars and hinges, this railing was beaten into shape by negro blacksmiths in the city's forges.
These "brute negroes," as they were called, were masters of their craft, and throughout the oldest ironwork is most beautifully wrought.
http://www.frenchcreoles.com/LouisianaPeople/Blacksmiths/blacksmiths.htm