According to Deadline, HBO has put the kibosh on one of two Game of Thrones prequel shows it currently has in development. This'd be the one written by Jane Goldman and starring Naomi Watts, which was said to take place thousands of years before the events covered in HBO's original Game of Thrones series.
But don't worry, Game of Thrones enthusiasts - there may yet be more Thrones in store for you: another prequel, set 300 years before the events depicted in HBO's original series, is apparently still in play. Created by George RR Martin and Ryan Condal, that series apparently "tracks the beginning of the end for House Targaryen."
As for why the plug was pulled on the Goldman/Watts Game of Thrones prequel, well, that remains unclear. HBO has not confirmed their decision not to move forward with the series, but Deadline says Goldman's been emailing cast and crew about the development, so expect a formal announcement sometime soon. Then again, maybe not! Shows don't make it past the pilot stage all the time.
Anyway, we'll keep you informed as further updates roll in. Stay tuned.