Islam was introduced to the northern Somali coast early on from the Arabian peninsula, shortly after the hijra whereupon Zeila's 7th century two-mihrab Masjid al-Qiblatayn was built and they were granted protection by the Aksumite King Aṣḥama ibn Abjar. In the late 9th century, Al-Yaqubi wrote that Muslims were living along the northern Somali seaboard. He also mentioned that the Adal kingdom had its capital in the city, suggesting that the Adal Sultanate with Zeila as its headquarters dates back to at least the 9th or 10th century. According to I.M. Lewis, the polity was governed by local Somali dynasties, who also ruled over the similarly-established Sultanate of Mogadishu in the littoral Benadir region to the south. Adal's history from this founding period forth would be characterized by a succession of battles with neighbouring Abyssinia. The largest sample by Pew Research Center on Muslim affiliation in the Horn was attained in Ethiopia which found that 68% adhered to Sunnism, 23% were non-denominational Muslims, whilst another 4% adhere to other sects such as Shia, Quranist, Ibadi etc.