Khalid ibn al-Walid is often presented as a infallible general who single handedly led the armies of Islam to victory in over a 100 battles (a number so often emphasised that it has a strong implication of propoganda). With divine support of course.

How reliable are the accounts by historians about him? How justified is the praise he is getting as a strategist? Do we only have Muslim Arab (and later: Muslim Persian) accounts about him? Do we have any non-muslim accounts ?