According to the mythology, Mohammad founded Islam in Mecca, moved to Medina, and culminated his career as a military and political leader who plundered and conquered all of Arabia. (Tellingly, the Muslim calendar starts from the move to Medina!) According to history, Islamic scholars started to document and solidify the religion 150-200 years after Mohammad, when a pure Arab hegemony gave way to an Arab/Persian fusion cemented by the myths of Mohammad. In either case, Islam is a state religion created to justify power and the oppression of non-Muslims.
What do we find when we examine the doctrines and practice of Islam? Mark Alexander has written an excellent review comparing Islam with other political ideologies. You decide! (Hat tip: AOW.)