Khalid won around 50 pitched battles in his life. He was outnumbered in more than 90% of them. He faced the might of the Sasanian and Byzantine Empires but managed to outmaneuver and defeat every army that came against him. His enemies were always better equipped and trained then his own men but he still won. He also used nearly every tactic in the book successfully (double envelopment, single envelopment, oblique order, psychological warfare etc). I am sure this puts him at no. 1 on any list of great generals. What do you think?