Although anaesthesia was discovered in 1846, pain relief had been used for many years previously. Opium, mandragora, and Indian hemp amongst others have been used since the earliest times as alluded to by many of the classical writers. The use of refrigeration anaesthesia is known to have been recommended a millennium ago although it never had much usage. Very soon after the introduction of ether anaesthesia, it was recommended for military use and the first use by the American forces was in Buena Vista early in 1847 and then again at Vera Cruz. Pirogoff taught and used ether anaesthesia on active service with the Russian forces in the Caucasus in the summer of 1847. Meanwhile Spencer Wells, who was serving with the Royal Navy in Malta, was the first British service medical officer recorded to have used anaesthesia. He went on to write up a series of 106 anaesthetics. The Danes were probably next to use anaesthesia in battle using chloroform in 1848. However, it was not until the Crimean War that anaesthesia began to play an important part in battle surgery with many anaesthetics being given with varying results. The War of the Rebellion was the next war in which anaesthesia was important and the first one in which proper statistics were kept allowing useful analysis. Anaesthesia had irrevocably found its place in battlefield surgery.