Donncoirce was probably king of Dál Riata

Dál Riata

Dál Riata was a Gaelic overkingdom on the western coast of Scotland with some territory on the northeast coast of Ireland...

 until his death in 792.

Donncoirce's death, the only report of his existence, appears in the Annals of Ulster

Annals of Ulster

The Annals of Ulster are annals of medieval Ireland. The entries span the years between AD 431 to AD 1540. The entries up to AD 1489 were compiled in the late 15th century by the scribe Ruaidhrí Ó Luinín, under his patron Cathal Óg Mac Maghnusa on the island of Belle Isle on Lough Erne in the...

for the year 791, corresponding with 792 AD. In it he is called "Donncoirce, king of Dál Riata. Donncoirce is not listed as a king in the Synchronisms of Flann Mainistrech

Flann Mainistrech

Flann Mainistrech was an Irish poet and historian.Flann was the son Echthigern mac Óengusso, who had been lector at the monastery of Monasterboice , in Irish Mainistir Buite, whence Flann's byname, meaning "of Monasterboice"...

, or in the Duan Albanach

Duan Albanach

The Duan Albanach is a Middle Gaelic poem found with the Lebor Bretnach, a Gaelic version of the Historia Brittonum of Nennius, with extensive additional material ....

, nor does he appear under this name in any surviving genealogies. Likewise, he was not a king of the Dál nAraidi

Dál nAraidi

Dál nAraidi was a kingdom of the Cruthin in the north-east of Ireland in the first millennium. The lands of the Dál nAraidi appear to correspond with the Robogdii of Ptolemy's Geographia, a region shared with Dál Riata...

 misreported as a king of Dál Riata, or otherwise associated with Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, as proposed by John Bannerman.

Alan Orr Anderson

Alan Orr Anderson

Alan Orr Anderson was a Scottish historian and compiler. He graduated from the University of Edinburgh. The son of Rev. John Anderson and Ann Masson, he was born in 1879...

 suggested that the name Donncoirce may be a byname, perhaps meaning "Brown Oats".

Donncoirce is the last king of Dál Riata so called by surviving Irish annals

Irish annals

A number of Irish annals were compiled up to and shortly after the end of Gaelic Ireland in the 17th century.Annals were originally a means by which monks determined the yearly chronology of feast days...

.

Dauvit Broun

Dauvit Broun

Dauvit Broun is a Scottish historian, Professor of Scottish History at the University of Glasgow. A specialist in medieval Scottish and Celtic studies, he concentrates primarily on early medieval Scotland, and has written abundantly on the topic of early Scottish king-lists, as well as on...

's reconstruction of the late Dál Riata kings places the beginning of Donncoirce's reign at the death of Fergus mac Echdach

Fergus mac Echdach

Fergus mac Echdach was king of Dál Riata from about 778 until 781.He succeeded Áed Find. He is stated to have been a son of Eochaid mac Echdach, and thus a brother of Áed. Some much later sources make him a son of Áed, but this is not credited by modern studies...

in 781 or 782.