In 224 AD, the Sasanian Empire gained control over the territories surrounding the Persian Gulf. Qatar played a role in the commercial activity of the Sasanids, contributing at least two commodities: precious pearls and purple dye. Under the Sasanid reign, many of the inhabitants in Eastern Arabia were introduced to Christianity following the eastward dispersal of the religion by Mesopotamian Christians. Monasteries were constructed and further settlements were founded during this era. During the latter part of the Christian era, Qatar comprised a region known as 'Beth Qatraye' (Syriac for "house of the Qataris"). The region was not limited to Qatar; it also included Bahrain, Tarout Island, Al-Khatt, and Al-Hasa.