The root of the conflict between the Christian Abyssinians and the Muslim peoples of Adal actually dates much earlier to the 9th or 10th centuries when Zeila was still Adal s headquarters Many centuries of trade relations with Arabia began with the establishment of commercial colonies along the coast by the Himmyarite kingdom and these eventually developed into the two small states of Zeila or Adal in the north and Mogadishu in the south where local dynasties of Somalized Arabs or Arabized Somali ruled The kingdom of Zeila centre of the Adal Sultanate is mentioned under this name first by Al Yaqubi then in the second half of the 10th century references occur in al Istakhri Ibn Hawqal and al Muqaddasi Later descriptions come from Ibn Said Maqrizi and Abu l Fida The Adal Sultanate with its capital Zeila thus appears to date from the 9th or 10th century and its history from its origins is the chronicle of a series of wars with Abyssinia