Sir James Simpson was a general of the British Army

British Army

The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

.

He served with the 1st Regiment of Foot Guards during the Peninsular War

Peninsular War

The Peninsular War was a war between France and the allied powers of Spain, the United Kingdom, and Portugal for control of the Iberian Peninsula during the Napoleonic Wars. The war began when French and Spanish armies crossed Spain and invaded Portugal in 1807. Then, in 1808, France turned on its...

 and the Waterloo Campaign, and then commanded the 29th Regiment of Foot

29th Regiment of Foot

The 29th Regiment of Foot was, from 1694 to 1881, an infantry regiment of the British Army. It now forms part of the Mercian Regiment.-Formation:...

 in Mauritius and Bengal.

In February 1855 he was sent out to the Crimea to act as chief of staff

Chief of Staff

The title, chief of staff, identifies the leader of a complex organization, institution, or body of persons and it also may identify a Principal Staff Officer , who is the coordinator of the supporting staff or a primary aide to an important individual, such as a president.In general, a chief of...

 to the army commander Lord Raglan

FitzRoy Somerset, 1st Baron Raglan

Field Marshal FitzRoy James Henry Somerset, 1st Baron Raglan, GCB, PC , known before 1852 as Lord FitzRoy Somerset, was a British soldier.-Early life:...

. Raglan died on 28 June, and Simpson reluctantly took command of the army. He resigned on 10 November, and was succeeded by Sir William Codrington

William John Codrington

General Sir William John Codrington GCB was a British general and politician who served in the Crimean War.-Military career:...

.