The Hadiya Sultanate (r. ~13th century – 19th century) also known as Adea or Hadia was a medieval kingdom located in southwestern Ethiopia, south of the Abbay River and west of Shewa. By 1850, Hadiya is placed north-west of lakes Zway and Langano but still between these areas. Hadiya was historically like the state of the Adal federation and a opponent of Abyssinia.

The Hadiya Kingdom was described in the mid-fourteenth century by the Arab historian Chihab Al-Umari as measuring eight days' journey by nine, which Richard Pankhurst estimates was 160 by 180 kilometers. Although small, Hadiya was fertile with fruit and cereals, rich with horses, and its inhabitants used pieces of iron as currency. It could raise an army of 40,000 cavalry and at least twice as many foot soldiers.

History
Hadiya was likely part of the domain of the Sultanate of Shewa and linked to the Harla before the pagan Kingdom of Damot's invasion led by Sidama. A cluster of speakers labelled Hadiya-Sidama developed, maintaining Islamic identity and later creating the Hadiya Sultanate. According to Hadiya elders the dynasty was started by descendants of Harar Emir Abadir, who intermarried with Sidama. The earliest surviving mention of Hadiya is in the Kebra Nagast (ch. 94), indicating that the kingdom was in existence by the 13th century. Another early mention is in a manuscript written on the island monastery of Lake Hayq, which states that after conquering Damot, Emperor Amda Seyon I proceeded to Hadiya and brought it under his control using Gura armies from modern Eritrea which would later become Gurage region. Later during Amda Seyon's reign, the King of Hadiya, Amano, refused to submit to the Emperor of Ethiopia. Amano was encouraged in this by a Muslim "prophet of darkness" named Bel'am. Amda Seyon subsequently set forth for Hadiya, where he "slew the inhabitants of the country with the point of the sword", killing many of the inhabitants while enslaving others. Despite such punitive measures, many of the Hadiya people served in the military units of Amda Seyon.

In the fourteenth century according to professor Lapiso Delebo, the Hadiya state within the "Hadiya-Harla Sultanate" maintained one of the largest armies in the region, consisting of 80,000 infantry and 40,000 cavalry. During the reign of Zara Yaqob, the Garad or Sultan of Hadiya, Mahiko, the son of Garaad Mehmad, repeated his predecessor's actions and refused to submit to the Abyssinian Emperor. However, with the help of one of Mahiko's followers, the Garaad was deposed in favor of his uncle Bamo. Garaad Mahiko then sought sanctuary at the court of the Adal Sultanate. He was later slain by the military contingent Adal Mabrak, who had been in pursuit. The chronicles record that the Adal Mabrak sent Mahiko's head and limbs to Zara Yaqob as proof of his death.

After militarily occupying Hadiya, many kings of Ethiopia and high ranking members converted and married Hadiya women; Princess Eleni of Hadiya is one example. This would escalate pre-existing tensions with the neighboring Adal Sultanate, who did not take kindly to the atrocities committed by Ethiopia against its fellow Muslim state. Adal attempted to invade Ethiopia in response, however the campaign was a disaster and led to the death of Sultan Badlay ibn Sa'ad ad-Din at the Battle of Gomit. Ethiopian and Adal relations continued to sour after the Hadiya incident and reached its peak at the Ethiopian–Adal war, where the Hadiya would join the Adal armies in their invasion of Ethiopia during the sixteenth century. It was revealed during Adal's invasion that the Hadiya state under Abyssinia was forced to pay yearly tribute by offering a Muslim girl to be converted to Christianity. Emperor Sarsa Dengel suppressed a rebellion by Hadiya leader Garad Aze which involved Hadiya ally Sultanate of Harar at the Battle of Hadiya. 

In the 1600s the Garad of Hadiya Sidi Mohammed defeated the troops of Emperor Susenyos I thus protecting their frontier from Abyssinian annexation for the next three hundred years. In the late sixteenth century, some parts of the Hadiya region was overrun by the Oromo expansion, thus, the Arsi Oromo today claim Hadiya ancestry. However the Hadiya Muslim cluster state existed until the Abyssinian invasion under Menelik II in the 1800s.

Identity
Historical definition of Hadiya people includes a number of Ethiopian ethnic groups currently known by other names according to ethnologist Ulrich Braukämper, who lived in various parts of southern-central Ethiopia for over four years during his research. In his book titled A history of the Hadiyya in Southern Ethiopia, he established linkages to the ancient Hadiya Kingdom. Currently, Hadiya is not a homogeneous ethnic group but is rather sub-divided into a number of ethnonyms, partly with different languages and cultural affiliations. They were initially all inhabitants of a single political entity, a Sultanate, which in the 4th centuries following its break-down became remarkably diverse. The Libidoo (Maräqo), Leemo, Sooro, Shaashoogo, and Baadawwaachcho remained a language entity and preserved an identity of oneness, the Hadiya proper; whereas the Qabeena, Allaaba, Siltʼe people, clans of Hadiyya origin in Welayta, Wolane occupied by the Gurage in the east as well as descendants of an old Hadiya stratum living with the Oromo and Sidama developed separate ethnic identities. Hadiya are related to the Harari.

Famous members
 Eleni of Ethiopia
 Garad Aze
 Garad Sidi Mohammed
 Garaad Amano
 Garaad Mehmad
 Garaad Mahiko
 Garaad Bamo

See also
 Silte people
 Silte Zone
 Silte language

Notes

References
Braukämper, Ulrich. (1980), Geschichte der Hadiya Süd-Äthiopiens: von den Anfängen bis zur Revolution 1974, Wiesbaden: Franz Steiner Verlag (Studien zur Kulturkunde 50).
Braukämper, Ulrich. (2005), "Hadiyya Ethnography", in: Siegbert Uhlig (ed.): Encyclopaedia Aethiopica, vol. 2: D-Ha, Wiesbaden: Harrassowitz Verlag. pp. 961–963.
Braukämper, Ulrich. (2005), "Hadiyya Sultanate", in: Siegbert Uhlig (ed.): Encyclopaedia Aethiopica, vol. 2: D-Ha, Wiesbaden: Harrassowitz Verlag. pp. 963–965.

Former monarchies of Africa
History of Ethiopia
Southern Nations, Nationalities, and Peoples' Region
Ethnic groups in Ethiopia