Around what time period did oil begin to be refined and become a very important resource? More importantly, when did it become important to the world's military forces?
it is said the refining of kerosene saved the last of the whale populationsThe late 19th Century, as I recall, with the rise of oil fuelled lamps.
Oil became useful as a source of lamp oil in the latter half of the 1800s. It became important as a resource with the rise of the internal combustion engine in the first three decades of the 20th Century, in particular during and after WWI.