"The Twilight of the Grey Gods", also known as "The Grey God Passes", is a short story by American writer Robert E. Howard that blends history and fantasy. Published posthumously in 1962, the first appearance of the story was in a collection titled Dark Mind, Dark Heart, edited by August Derleth. The tale is a fictionalized version of the Battle of Clontarf (1014) recast in Howard's views, with doomful visions and weird fantasy elements. While the historical facts of the battle are accurate, they are not the most important parts of the story. The protagonist is Conn the Thrall, who fights alongside Turlogh Dubh O'Brien, a recurring character of Howard's who is an outcast from Brian Boru's clan. Howard first wrote a version of this story called "Spears of Clontarf", but it was rejected by "Soldiers of Fortune" magazine. He then added fantasy elements to the story so as to be able to submit it to the Weird Tales magazine under the title The Grey God Passes, where it was also rejected by editor Farnsworth Wright in December, 1931. He then rewrote it a third time, as a horror story called The Cairn on the Headland, and that version was published in the January, 1933 issue of Strange Tales. Howard's first version (as Spears of Clontarf) finally saw print in a chapbook in 1978, and his Grey God Passes version was also published posthumously in the anthology collection titled Dark Mind, Dark Heart in 1962.[1] Source: Wikipedia (en)