Who discovered niobium and why was it originally called columbium?

Niobium was discovered in 1801 by the English chemist Charles Hatchett. He originally named the element columbium in honor of the United States, as "Columbia" was a common synonym for the country where the ore sample originated.12

While the name columbium persisted for a long time—particularly within the U.S. metallurgical industry—it was eventually determined that the element was identical to one later named niobium by German chemist Heinrich Rose in 1844. Rose chose the name niobium after Niobe, the mythological daughter of Tantalus, reflecting the element's close chemical relationship with tantalum. An international agreement reached around 1950 officially established "niobium" as the standard name for the element.2