In Irish mythology, Donn ("the dark one", from Proto-Celtic: *Dhuosnos)[1][2] is an ancestor of the Gaels and is believed to have been a god of the dead.
Folklore about Donn survived into the modern era in parts of Ireland, in which he is said to be a phantom horseman riding a white horse.
[7] In their translation of Acallam na Senórach, Ann Dooley and Harry Roe commented that "to go to the House of Donn in Irish tradition means to die".
[8] Tech Duinn may have been thought of as a place where the souls of the dead gathered before travelling to their final destination in the otherworld, or before being reincarnated.
During their invasion, Donn slights Ériu, one of the eponymous goddesses of Ireland, and he drowns in a shipwreck off the southwest coast.
The Metrical Dindshenchas entry for "Tech Duinn" recounts the tale:Through the incantations of the druids a storm came upon them, and the ship wherein Donn was foundered.
[2] Donn is the father of Diarmuid Ua Duibhne, whom he gave in fosterage to the god of youth, Aengus mac Óg, to raise.
[2] In modern Irish donn is the most common word for the colour brown, and by extension can also mean "sturdy (like) wood".