The 90th were called from China to India in 1857, to help put a stop to the Indian Mutiny.
The Indian Mutiny began on 10th May 1857, in Meerut. It was started by a group of Indian army soldiers, who were angry over changes to their ammunition. New cartridges, coated in cow or pig fat, had been issued to them. At that time a soldier had to bite on the cartridge before using it, and doing so would mean biting on the fat. This was against Hindu beliefs about eating beef, and Muslim beliefs about eating pork. Indian soldiers were also dissatisfied over changes to their terms of working and pensions.
With its various and complex causes the Mutiny soon spread, leading on to other mutinies and civilian rebellions.
Lucknow was the home of the British Commissioner for the Territory, making it a significant place. The First and Second Siege of Lucknow formed a large part of the Indian Mutiny, where the 90th were part of both the besieged and relieving forces.
The 90th played an important part in putting an end to the uprising, but also paid a heavy price. They lost 326 men, both through battle and disease.
The Regiment remained in India until 1869, when they returned to Edinburgh.