Alcatraz Island Engineers began fortifying the island, work which continued until 1858, eventuating in Fortress Alcatraz. The island's first garrison at Camp Alcatraz, numbering about 200 soldiers and 11 cannons, arrived at the end of that year. When the American Civil War broke out in 1861, the island mounted 85 cannons (increased to 105 cannons by 1866) in casemates around its perimeter, though the small size of the garrison meant only a fraction of the guns could be used at one time. At this time it also served as the San Francisco Arsenal for storage of firearms to prevent them falling into
Alcatraz Federal Penitentiary legendary prison" suited to the times, which resulted in the Alcatraz Island Federal Penitentiary being nicknamed "Uncle Sam's Devil's Island." Despite Alcatraz being designed to house the "worst of the worst" of criminals who caused problems at other prisons, under the guidelines and regulations set by the strict prison administrators, courts could not direct a prisoner to be directly sent to Alcatraz, however notorious they were for misbehavior and attempted escape from other prisons. Prisoners entering Alcatraz would undergo vigorous research and assessments prior to their arrival. Security in the prison was very tight, with the constant checking of bars,