Original sentence: The history of Arabs in Afghanistan spans over one millennium, from the 7th century Islamic conquest when ethnic Arab fighters battled and migrated to the area  till the recent Soviet-Afghan War when they assisted fellow Muslims in fighting the Soviets and pro-Soviet Afghans, to becoming the instruments of torment of the average civilian Afghans in their role as al-Qaeda functionaries and terrorists
Edited sentence: The history of Arabs in Afghanistan spans over one millennium, from the 7th century Islamic conquest when ethnic Arab fighters battled and migrated to the area  till the recent Soviet-Afghan War when they assisted fellow Muslims in fighting the Soviets and pro-Soviet Afghans