How long was Washington DC know as Washington City ?

Question

A history test question ?

Answer 1

The city was officially named "Washington" on September 9, 1791. Out of modesty, George Washington never referred to it as such, preferring to call it "the Federal City."

The District of Columbia, founded on July 16, 1790, is a federal district as specified by the United States Constitution.

So technically, the District of Columbia existed before the city was named Washington. So it has always been Washington DC. In 1878, Congress passed an Organic Act that made the boundaries of the city of Washington coterminous with those of the District of Columbia.

http://en.wikipedia.org/wiki/Washington_D.C.