He may also have used the name Paul because the Greek pronunciation of his Hebrew name, Saul, is very similar to that of a Greek word that has a bad connotation.
فقد أُوكل اليه إعلان البشارة لغير اليهود ،‏ وربما شعر ان استخدام اسمه الروماني سيكون له وقع افضل .‏