Brigantia was a nature goddess, differentiated in later times into a triad of sisters, the Brig of Fire, of Life, and of Valour... The great people of the Brigantes derived their name from the same root, Gaelic bríg, signifying valour. (The Lives of the British Saints, Baring-Gould, v.1, 1907)

... The goddess Brigantia may have been a tribal goddess of the Brigantes, and it is noticeable that her name is identical in form with the Irish Brigit.  She is mentioned on an inscription, of A.D. 205, at Greetland, and on another inscription, at Adel, near Leeds, while, on an inscription in Cumberland, she is called Dea Nympha Brigantia.  A further inscription of the second century, found at Birrens, near Middleby, reads Brigantiae sacrum. (Cambridge Medieval History, v.2, 1913)