From the ArcaMax Publishing, The Culinary World, with Chef James Newsletter:
http://www.arcamax.com/news/chefjames/s-314091-152651
Ciudad Bolivar is a city in east Venezuela, founded in 1764 as San
Tomas de la Nueva Guayana, it was popularly known as Angostura. Here
in 1824 a physician first made Angostura Bitters, an aromatic
flavoring agent used in drinks and in cooking.
Courtesy of FoodReference.com.