¹⁰Cross, Tom Peete, and Clark Harris Slover. Ancient Irish Tales. New York: Barnes & Noble, 1936. 374.
"The Pursuit of Diarmuid and Gráinne" as translated in Ancient Irish Tales may be read in its entirety here.
Gráinne's name may come from that of the sun goddess, Grian. Diarmuid's full name is usually given as "Diarmuid Ua Duibhne," but some credit an ancient source for his alternate name of Diarmaid Donn, derived from Donn, the Celtic god of the dead. (Ó hÓgáin Dáithí. Fionn Mac Cumhaill: Images of the Gaelic Hero. Dublin: Gill and Macmillan, 1988. 166-75.)
Some have suggested that "The Pursuit of Diarmuid and Gráinne" had some influence on the Tristan and Iseult legend. Although that story developed in France during the 12th century, it is set in Britain. There are also parallels to the story of Lancelot and Guinevere.