The East coastal communities of North Sumatera had accepted the influence of Islam through its introduction with merchants from Arabia / Persia and India since the 7th-8th century AD. The process of Islamization finally formed a political community patterned in Islam in the 13th century AD by the emergence of Kingdom of Haru. Islamization in Simalungun Regency only occurred around the 17th century AD with the founding of the Silindrik Gravestone at the State Museum of Pematang Siantar. However, the concrete data about the existence of Muslim communities or Simalungun people who had converted to Islam were only recorded in the Dutch colonial report in the mid-19th century AD. It is very surprising, for the time span reached two hundred years. Likewise when compared with the Islamization that had prevailed in the East coast of Sumatra
Keywords: Islamization; ancient; Arabia/Persia; Simalungun Regency
