Completed in 1857 the ship participated in the Second Italian War of Independence two years later.

The conversion to steam power involved cutting the ship's frame in half amidships and building a new section to house the propulsion machinery and coal bunkers, which reduced her armament to 90 guns.

On the quarterdeck and forecastle were twenty 30-pounder cannon and a pair of 163 mm (6.4 in) rifled muzzle-loading guns.

She was laid down at the Arsenal de Rochefort on 30 May 1848 and was ordered to be converted to steam power on 19 October 1854.

Alexandre was commissioned on 1 March although her sea trials did not begin until 14 April 1858.