This question needs more context in order to be answered; it needs a time reference. Try re-phrasing the question.
The Arab or Muslim armies conquered so quickly because of their size and the ability to move quickly over wide areas. The cavalry was especially effective.
The armies were known as the Arab Nomads, Jihadis, or Mujahedin.
No.
They invaded Israel.
711 - 712 AD
1279
1279
1279
1279
Clovis was the first king of the Franks to conquer large areas.
Arab armies attacked to restore Arab influence in India
Seven Arab armies invaded.