Islam was introduced to the Horn of Africa early on from the Arabian peninsula, shortly after the hijra. At Muhammad's urging, a group of persecuted Muslims were received at the court of the Ethiopian Christian King Aṣḥama ibn Abjar, a migration known as the first Hijarat. Zeila's two-mihrab Masjid al-Qiblatayn was built during this period in the 7th century, and is the oldest mosque in the city. 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 centuries.