 Complete the following phrase:  The Late sixteenth century saw Oromos invading regions of Somalia from southern portions such as Lower Juba, incorporating the Harla people. In 1577 Harla would move the Adal capital to the oasis of Aussa, and later create the Imamate of Aussa before being overthrown by the Mudaito dynasty in the eighteenth century. In 1893 British led expeditions, came across an ancient town in Nugaal Valley, Somaliland, the local Dhulbahante tribe alleged the Harla had lived in the area before the Oromo invasions. In 2017, a Harla town that produced jewelry was discovered by archaeologists. The architecture of a mosque found affirmed Harla had ties with Islamic centers in Tanzania and Somaliland. The Harla tribes disappearance could have been due to the 