Briefly: HBO has just renewed Game of Thrones for a fourth season.
The announcement was made by Michael Lombardo, president of HBO Programming. A premiere date has not been set, but you can expect it to be around March/April 2014.
HBO’s press release marking the announcement notes the high ratings for the season three premiere this past Sunday. Game of Thrones season 3 premiere “topped the series’ highs, with record viewership for both the 9:00 p.m. (ET/PT) airing and gross audience across the three plays. At 9:00 p.m., it averaged 4.4 million viewers, outperforming (+4%) the previous high of 4.2 million viewers from last season’s finale.”