Harland and Wolff built Leicestershire in Belfast for the Bibby Steamship Company, launching her on 3 June 1909 and completing her on 11 September.

[4] As built, Leicestershire had capacity for 230 passengers,[4] 1,629 cubic feet (46.1 m3) of her hold space were refrigerated,[5] and her tonnages were 8,299 GRT and 5,165 NRT.

She brought the 17th Lancers from Bombay to Marseille, and then took part of Indian Expeditionary Force D, including Burmese troops, to the Persian Gulf.

[11] On 11 October 1917 she accidentally rammed HMY Kethailes in the Irish Sea off the east coast of County Wexford, sinking the yacht and killing 17 of her crew.

The UK ran military operations in the Mediterranean and Middle East theatre of World War II from Egypt, and held authority over Egyptian merchant ships.

[11] In March 1941 Zamzam's return voyage to Egypt was delayed when a stevedore claimed he had suffered a skull fracture while working aboard her.

[20] One missionary wife, Lillian Danielson, found that the lifejackets in her cabin were in poor condition and were too large to fit her six children, whose ages at the time ranged from one to 10.

Her Master, William Gray Smith, sought permission for her to sail fully lit as a neutral ship.

[11][23] Zamzam called at Recife, where passengers joined the ship including Fortune reporter Charles Murphy and Life photographer David Scherman.

Captain Gray stated that this was because her wireless operator received a distress message from a Norwegian merchant ship, the Tai-Yin, that was under attack by a German raider.

[29] At about 0555 hrs on 17 April the German auxiliary cruiser Atlantis opened fire on Zamzam from a range of about 3.5 nautical miles (6 km).

[30] Nine 150 mm shells hit Zamzam' port side, injuring several passengers and crew, including the ship's doctor.

[32] The damaged boats were swamped shortly after being launched,[32] including that carrying Mrs Danielson and her children, all of whom ended up in the water.

[17] The ambulance drivers looked after women and children, treated the wounded, and pulled people out of the sea into the boats and liferafts.

Atlantis' Captain, Bernhard Rogge, sent a boarding party aboard Zamzam that searched her chartroom and Master's quarters,[34] removed supplies and personal possessions.

[17] The next day Atlantis met her supply ship, Dresden  [de], to whom all Zamzam's survivors and their luggage were transferred except three who were too seriously wounded.

A delegation of survivors met Rogge on Atlantis and asked for more food to be transferred to Dresden, and for the US and other neutral survivors to be put ashore in South America to avoid the danger Dresden would face when running the Royal Navy blockade to reach Europe.

[22][39] the UK Ministry of Information said she must be "presumed lost", but naval authorities in Cape Town insisted she was merely "overdue".

[11] On 21 May the Deutsches Nachrichtenbüro [de] ("German News Office" or DNB) admitted the Kriegsmarine had sunk Zamzam and confirmed that its passengers and crew were in occupied France.

[26] On 9 June Murphy, Scherman[41] and a representative of the Ambulance Corps flew home from Portugal on a Pan American Clipper via Horta and Bermuda to LaGuardia Airport, New York.

[50] The largest group was of 53 survivors who sailed from Lisbon on the American Export Lines ship Exeter,[51] which reached New York on 24 June.

[11] On 23 June Life published an extensive article about Atlantis sinking Zamzam and Dresden taking survivors to France.

[11][52] Two of the ambulancemen escaped internment in France, travelled to Portugal, and on 28 July reached New York aboard the American Export Lines ship Excalibur.

The Germans released the remaining ambulance drivers whom Dresden had landed in France; they sailed home on West Point's return voyage from Lisbon[53] and reached New York on 2 August.

[54] UK reconnaissance aircraft used Scherman's photographs to identify Atlantis, and the cruiser HMS Devonshire sank her on 21 November 1941.

[11] The German censor had released the photographs Scherman took aboard Dresden, and on 15 December Life published them in an article.

[11][38] The two wounded survivors, Robert Starling from the UK and US ambulanceman Frank Vicovari, were still aboard Atlantis when Devonshire sank her.

The German submarine U-126 surfaced, took aboard 107 of the survivors and started to tow the rafts or boats toward neutral Brazil.

[55] In this way Vicovari,[11] and presumably Starling, reached German-occupied France, but only after the Japanese attack on Pearl Harbor on 7 December and US declaration of war on Germany four days later.

In June 1942 ten Canadian women passengers from Zamzam sailed from Lisbon to Jersey City on the Swedish liner Drottningholm, which the US Department of State and US Maritime Commission had chartered to exchange interned civilians from both sides.