The ''Kingdom of Adal'' (also ''Awdal'', ''Adl'', or ''Adel'') was centered around Zeila, its capital. It was established by the local Somali tribes in the early 9th century. Zeila attracted merchants from around the world, contributing to the wealth of the city. Zeila is an ancient city and it was one of the earliest cities in the world to embrace Islam, shortly after the hijra. Zeila's two-mihrab Masjid al-Qiblatayn dates to the 7th century, and is the oldest mosque.