General knowledge of terrain has always been important to military intelligence. But environmental factors sometimes went unnoticed. At the Battle of Agincourt mud was a major factor in the English victory. The extremely muddy ground slowed down the French and made them easy prey for English archers. In the 17th and 18th centuries army quartermasters, in addition to providing supplies, also scouted terrain and planned s the army would take. One of the first major improvements in gaining scientific knowledge of terrain was during the Russo-Japanese War (1904–1905). The Russians used geologists to do a detailed survey of Korea. They also used geologists to advise them in building fortifications.