She had been built as Principe di Piemonte by Laing James & Sons Ltd. at Sunderland, launched on 28 February 1907 and completed on 19 June. Her dimensions were modest by Edwardian transatlantic standards: 131 metres long, 16 metres in beam, 7.6 metres deep, with two triple-expansion steam engines driving twin screws at a top speed of 14 knots. Two masts, two funnels, accommodation for 120 first-class, 50 second-class, and 1,500 steerage passengers. Her maiden voyage on 19 June 1907 took her from Genoa via Naples and Palermo to New York - the standard Italian emigrant trade of the era. On 17 July 1912 a steam pipe from one of her boilers burst en route to New York, killing the first engineer, the chief of the firemen, and three stokers. Five years before she met a U-boat she had already taken her first lives.

Her final voyage under Italian ownership ended on 12 December 1913. The Uranium Steamship Company bought her in 1914 to replace another vessel lost to fire. Now named Principello, she sailed Rotterdam to New York via Halifax from February 1914 onwards, then switched to the Avonmouth-New York run in April 1915. In 1916, with Cunard hemorrhaging vessels to German U-boats, she was transferred to the company's flag, renamed Folia, and converted to a primarily cargo role. A 12-inch deck gun was installed so she could - in theory - defend herself. She was now classified as a defensively armed merchant ship, a status that under the rules of unrestricted submarine warfare made her a legitimate target without warning.

She was commanded on her last voyage by Captain Francis James Daniel Inch, who had survived the wreck of the Volturno in 1913 - a fire-stricken liner whose loss had killed 136 passengers and crew in the mid-Atlantic. Inch had spent four years between disasters. He had loaded 4,400 tons of cargo in New York: trench-digging machinery and shell cases for the Western Front, plus general goods. He had brought his ship safely across the North Atlantic to within sight of the Irish coast. On the morning of 11 March 1917 his third officer spotted the periscope, the wakes appeared, and Inch had perhaps thirty seconds to register that the war he had thought himself nearly through with was about to claim his ship.

After the first torpedo struck, Inch ordered his men into the four remaining lifeboats. As the Folia settled in the water, the German submarine surfaced and circled. Her crew fired four shells from her deck gun and put another torpedo into the stricken ship. Then they departed. Inch regrouped his four lifeboats - seventy-eight men aboard - and ordered them to row for the Irish coast. They reached the shore by 11 a.m. The villagers of Ardmore took them in. By that evening the survivors were in Dungarvan, where the local community supplied them with food, clothes, and accommodation. Seven crew had died. Without the lifeboats and without the Ardmore villagers, seventy-eight more would have.

The wreck lies in 36 metres of water four miles from Ram Head. In 1977, the salvage firm Risdon Beazley extracted a vast quantity of brass bars from the ship - the operation did serious damage to the wreck. Local divers cleaned up the remaining brass in the 1980s. Most of the Folia now lies scattered as steel plates among shell casings; the bow remains one of the most intact features, alongside the boilers, which form the highest point of the wreck at five metres above the seabed. In 2014 the deck gun - the symbolic, useless 12-inch weapon that had been intended to protect her from the U-boat - was raised. It is now on display in Ardmore, the village whose villagers rowed her survivors ashore. Two of her propeller blades, also salvaged, can be seen in Dungarvan. The ship that touched three countries and three names in ten years ended up dispersed across a four-mile arc of County Waterford coast - the gun in the square that had failed, in the war that had killed her.