Game of Thrones is an American fantasy drama television series created for HBO by David Benioff and D. B. Weiss. It is an adaptation of A Song of Ice and Fire, George R. R. Martin's series of fantasy novels, the first of which is titled A Game of Thrones. The episodes are mainly written by Benioff and Weiss, who are the executive producers alongside Martin, who writes one episode per season. Filmed in a Belfast studio and on location elsewhere in Northern Ireland, Malta, Scotland, Croatia, Iceland, the United States, Spain and Morocco, it premiered on HBO in the United States on April 17, 2011. Two days after the fourth season premiered in April 2014, HBO renewed Game of Thrones for a fifth and sixth season.