Historia Brittonum
"Lebor Bretnach" is a translation of a 9th-century historical collection purportedly written by Nennius, the "Historia Brittonum", but not an entirely literal one. It only summarises the "Historia Brittonum" where that work deals with specifically Gaelic matters already familiar to scholars in Ireland and Scotland, and in some other passages it includes additional material taken from, for example, the "Sex Aetates Mundi", Bede's "Historia Ecclesiastica Gentis Anglorum", and a Pictish king-list.