Who is khalid bin walid?

he was one of the commander of the early rashidun chaliphate during the early Islamic conquests and one of the most successful general in history.he first defeated the rebels of Arabia in the ridda wars,then invaded the sassanid Persian empire and after winning a series of battles was transfered to the syrian front to fight the byzantine(roman) empire whom he fought and defeated.in his life time he conquered modern day Iraq,Kuwait,palestine,Israel,Jordan,Lebanon,syria and parts of south eastern turkey.he was never defeated in battle.