The second half of the 18th century saw the formation of the first establishments to provide formal training to officers prior to receiving their first commission. The first school, the Royal Military Academy, was formed in 1741 by the Board of Ordnance to train Artillery and Engineer Officers. It was 1800 before the army formed a similar establishment and the building blocks were in place for the creation of the Scientific Soldier. This thesis will look at the formation of the Royal Military Academy and look at the training that officers received with a focus on those officers destined to serve during the Peninsular War. The complementary roles and training of the Royal Military Artificers and the eventual formation of the School of Military Engineering will be described. A thorough review will then be undertaken of the officers in the Royal Engineers, the numbers, their background, the locations they served in and the tasks they carried out. A new review of the sieges during the war will be completed using unpublished material. The other roles undertaken by the Royal Engineers in the Peninsular War will be fully investigated and described. These roles are more comprehensive than has been commonly understood and will demonstrate the contribution of the educated officer to the war. The thesis will conclude by looking at the impacts of the post-war peace on military education.