The 17th century saw the inclusion of upland Harla and Doba populations playing a pivotal role in the establishment of the Aussa Sultanate.

Harar which had held the position of the capital for 58 years between 1519 and 1576, was too exposed to the frequent Oromo attacks and as a result, lost its strategic importance.

[5][6][7] Aussa in the late 16th century Arabic text of Harar "Taʾrīkh al-mulūk" was stated to be occupied by the Adalite holding the title Hegano and had already become a breeding ground for those opposing the rulers of the Harar-based Adal Sultanate.

With the help of the Mudaito, the Harla burnt the residence of Imam Salmän in Handág, which is believed to be located in Wablé Fánta, at the confluence of the Nangaltá and Afal-Gedé.

His successor was the ancestor of the Dúrussó fraction, Mahammad "Düs" (around 1750–1760), who became the first Harla "Sultan" of Awsa and was referred to as "Rais" in Arab chronicles.

[24][25] Italian scholar Enrico Cerulli asserts that although Aussa became dominated by the Afar people, the ancient Semitic speaking Muslim kingdom survived in the form of the Emirate of Harar past the 18th century.