Islam reached India through several routes. One was military: Arab forcesentered India as early as mid-seventh century even before theestablishment of the Umayyad caliphate, although their first expeditionswere exploratory ventures rather than campaigns of conquest. Sind, theIndus River Valley was conquered and with the rest of the dar-al-islam,Sind passed into the hands of the Abbasid caliphs. Sind was on the fringeof the Islamic world. Muslim merchants took their faith to coastalregions in both northern and southern India. Arab and Persian marinersvisited Indian ports as well. Migrations and invasions of Turkishspeaking peoples from central Asia. Some entered as mercenary soldiers.