Going into the annals of history you will not find the real Islam because most of the history of the exalted prophet and his companions was fabricated by the Persians and Jews. about 200 years later. They were conquered by the Arabs and did not have any love lost for the Arabs or their beliefs.
A believer does not have to go into the annals of history to prove his faith. Holy Quran has everything, including commandments, prophesies and historical facts to differentiate the truth from the fabricated stories.