Question: When did muslim armies invade syria and iraq?
Disambiguated questions and answers: question: When did Muslims led by general Khalid ibn al-Walid invade what is now Iraq?
When did Muslims later led by general Khalid ibn al-Walid invade what is now Syria?
answer: 633
May 634
Natural Questions answer: in 634 (from the Wikipedia article "Muslim conquest of the Levant")