Khalid`s enemies were almost always numerically superior and heavily armed equiped, despite being always outnumbered 3 to 1. He took Iraq from the Sassanids Persia`s and took Syria from the Byzantines.

In the Battle of Yarmouk, Khalid led 40,000 muslims against 200,000 Bayzantines Christians, using his agile mobile guard, he turned the tide and won. 


In the battle of Firaz at the borders of Byzantines and Sassanid Persians, Khalid led an army of 15000 muslims against the combined Persians and Byzantine army of 150,000 and won. Khalid is one the few undefeated generals in history.