Question: Mexican general, Gregorio Ruiz, fought against the ensuing empire of the younger brother of the Austrian emperor Francis Joseph I, the only what of the Second Mexican Empire?
Sentence (from "José Mariano Salas"): José Mariano de Salas (11 May 1797 – 24 December 1867) was a Mexican general and politician who served twice as interim president of Mexico (1846 and 1859).
Relevant evidence: No