Formidabile was the lead ship of the Formidabile-class ironclad warships, the first ships of that type to be built for the newly formed Italian Regia Marina (Royal Navy). Formidabile and her sister, Terribile, were both built in France; Formidabile was laid down in December 1860, was launched in October 1861, and was completed in May 1862. She was a broadside ironclad, equipped with four 203 mm (8 in) and sixteen 164 mm (6.5 in) guns.