Warnings of the growing discontent with the reign of Queen Isabella II of Spain were amplified with the violent mutiny of the enlisted men of the Spanish Army artillery's San Gil barracks just a hundred yards from the royal palace. Led by their non-commissioned officers, the mutineers shot many of their officers and mounted an attack, with cannon, on the Ministry of the Interior. They were driven back and the uprising put down. Around sixty executions followed. Queen Isabella was overthrown in September 1868. (By John Osborne)
"Spain," The American Cyclopedia and Register of Important Events of the Year 1866 (New York: D. Appleton and Company, 1873), 687.
H. Butler Clark, Modern Spain, 1815-1896 (Cambridge: Cambridge University Press, 1908), 294-296.