In second level history here in Ireland we were led to believe that through the utilisation of Flying Columns (and hit and run tactics) during the Irish war of Independence, that the IRA were the progenitors of modern Guerilla Warfare tactics, with these methods and tactics then taken and adapted in other conflicts/civil wars after this (the Spanish Civil war being mentioned in our text books at the time)
Is this true or are there any other documented examples pre War of Independence?
I've sort of touched on this before in this thread and like I mention in that thread, the Flying Columns was an already proven concept by the time of the Irish War of Independence. I feel like my previous answer should be able to answer your question, but I am more than happy to elaborate or answer any further questions.