This allowed the army some measure of self-sufficiency, and up through to the 19th century most of the ammunition a soldier needed for an entire campaign could be carried on their person. However this method led to an extensive baggage train which could slow down the army's advance and the development of faster-firing weapons soon outpaced an army's ability to supply itself. Starting with the Industrial Revolution new technological, technical and administrative advances led to a third method, that of maintaining supplies in a rear area and transporting them to the front. This led to a "logistical revolution" which began in the 20th century and drastically improved the capabilities of modern armies while making them highly dependent on this new syste