[1][2] Sandwith left Beverley in 1843, for the medical school at Hull, and spent a few months at Lille to learn French.

[1] In March 1849 Sandwith travelled to Constantinople with letters of introduction to Sir Stratford Canning, the English ambassador.

In August he accompanied Canning's protégé, Austen Henry Layard, in his second archæological expedition to Nineveh, and spent nearly two years in Mesopotamia.

In 1853 he was appointed correspondent of The Times, but John Thadeus Delane complained that he looked at the Eastern question from the Turkish point of view.

[1] When the Crimean War broke out, Sandwith served with Omar Pasha in 1853 in the River Danube campaign.

[1] In February 1855 Williams, now a lieutenant-general in the Turkish army, appointed Sandwith inspector-general of hospitals, placing him at the head of the medical staff.

Meanwhile, Colonel Henry Atwell Lake was fortifying Kars, and in the beginning of June, when the siege was imminent, Williams and his staff took up their quarters there.

During the Siege of Kars, which lasted till the end of November, Sandwith had to contend with cholera and starvation; and after the assault of 29 September he had wounded men, both Turkish and Russian, on his hands.

In August he went with Lord Granville to Moscow for the coronation of the czar, and was presented with the Russian order of St. Stanislaus.

[1] Changing career, in February 1857 Sandwith was appointed colonial secretary in Mauritius, and he spent two years there.

In 1872 he was invited by the municipality of Belgrade to attend the coronation of Milan I of Serbia, and became involved in Serbian politics.

[8] In October 1877 Sandwith went to Bucharest for three months, as agent for the England-Russian Sick and Wounded Society, a Red Cross organisation of the Russo-Ottoman War.

[1] Sandwith combined with Howard Evans and Frederick Maxse to lobby the Land Tenure Reform Association (LTRA) in 1876.

In 1880 the state of his wife's health led the couple to winter at Davos, but they were both ill; in the spring he became worse.