Originally, they were to be slightly larger than SS Leonardo da Vinci, which was then being built, but jet aircraft had not yet had a notable effect on the Mediterranean area and a pair of genuine superliners seemed desirable, both from a commercial point of view and to provide jobs to sailors and shipyard workers.

The smoke deflectors became popular in ship design during the 1970s and 1980s, whereas the idea of allowing wind to pass through the funnel was picked up again in the late 1980s and is almost the norm in modern shipbuilding.

On Tuesday morning, April 12, 1966, five days after having departed Genoa, Michelangelo, under command of Senior Captain Giuseppe Soletti, was hit by an unusually large wave during a storm in the mid-Atlantic, which caused the forward part of her superstructure to collapse, or to be pushed backwards, and killed passengers Dr. Werner Berndt of Hamburg, Germany and John Steinbach of Chicago.

During the following years, passenger numbers in the transatlantic trade declined steadily due to competition from the air, and more and more ships were withdrawn.

Italy's flagship SS Michelangelo made her last Atlantic crossing in July 1975, under command of Senior Captain Claudio Cosulich.

Several buyers (including Knut Kloster of Norwegian Cruise Line) inspected the ships, but did not wish to buy them due to the costs required to modernise them to cruise-ship standard.

One serious buyer, Home Lines, wished to buy the ships and keep them under Italian flag for cruising in the Caribbean.

In 1978, plans were made to reconstruct her as the luxury cruise ship Scià Reza il Grande (in honour of Rezā Shāh), but an expert team sent from Italy to inspect the ship came to the conclusion she was too badly deteriorated to make rebuilding a viable option.