Which world leaders bore the following nicknames?

The Liberator. Simon Bolivar (1783-1830), leader in the quest for Latin American independence; also, Daniel O’Connell (1775-1847), Irish nationalist leader in the British House of Commons.

The Hammer. Charles Martel (688-741?), Frankish ruler who stopped the Muslim invasion of Europe.

The Upright. Abu Bakr (c. 573-634), the first Muslim caliph and successor to Muhammad.

Mr. Republican. Robert Alphonso Taft (1889-1953), U.S. senator from Ohio, son of William Howard Taft, and coauthor of the Taft-Hartley Labor Act.