The Dane Hills lie two miles from the city center of Leicester by way of Glenfield Road. This area is now all built up but it was previously a wasteland consisting of a series of low sandstone hills. It is here the small cave of 10-12 feet across was known locally as Black Annis' Bower.
Black Annis was an ogress described in a poem by Leiutenant John Heyrick, quoted by John Nichols in his History of Leicester, as having a livid blue face. She had carved her cave out of the sandstone with her talons, and the blood of children and lambs stained the floor.
The ogress may be a distorted local memory of a real person. Nichols quotes the antiquary Burton's description of a church in Swithland that commemorates Anges Scott, there called Antrix:
This Anges Scott, as I guess, as an Anchoress; and the word Antrix in this epitaph, coined from antrum, a cave, wherein she lives; and certainly (as I have been credibly informed) there is a cave near Leicester, upon the west side of the town, at this day called Black Agnes Bower.
Others have followed the Revd John Dudley in believing Annius to be the Celtic goddess Anu. In his Naology he suggested that her devouring of children reflected cannibalistic rites once conducted here by the ancient British. He wrote that in 1846, before such rubbish has been disproven. There is no evidence at all that such rites took place.
A case may be made for Annis being one of the supernatural hags of British folklore. With her livid blue face, she resembles the Cailleach Bheur or Blue Hag of the Highlands, but that is about as much that can be said.
Whoever she was, in the 19th century Annus was generally known as "Black Anna." In 1874 a contributor to the Leicester Chronicle wrote:
Little children who went to run on the Dane Hills, were assured that she (Black Anna) lay in wait there, to snatch them away to her 'bower'; and that many like themselves she had scratched to death with her claws, sucked their blood, and hung up their skins to dry.
Black Anna was also thought to crouch in an old oak growing out of a cleft above her cave, waiting to spring out on passers-by.
By the end of the 19th century, this hag was also known as "Cat Anna", and said to be a witch living in the cellars under Leicester Castle. There was supposed to be a subterranean passage connecting the castle with the Dane Hills, along which she ran.