<span>Spirituality or religion. The pope endorsed the crusades, and the pope was viewed, in those times by everyone and in the modern day by Catholics, as the mouthpiece of god. As a result, the edict to take back the holy lands was viewed as divinely inspired. Religion was viewed, in those times, as a cornerstone for a moral life.</span>
Sources such as diaries though not very reliable can be used if there are a large amount of them showing the same date and event. Historical books written about the event especially those closer to the time would be able to help determine that the date is accurate as well.
