[SPOILERS for Vikings season three ahead.]
From writer/creator Michael Hirst (The Tudors), History's Vikings follows the rise to power of Ragnar Lothbrok (Travis Fimmel), who claims to be a descendant of the god Odin and becomes the King of the Viking tribes. History's stab at a scripted series proved consistently popular and successful over the course of its first three seasons, making the news of a fourth season renewal come as no surprise.
After keeping Ragnar in the background of the action toward the end of season 3, the viking seemingly turns his back on his heritage and asks to be baptized, before suddenly "dying." After his coffin is escorted into Paris to be blessed in the Paris Cathedral, Ragnar (who is very much alive), leaps up, kills the Archbishop and take Princess Gisla (Morgane Polanski) hostage before letting his men raid the city.
Season 3's cliffhanger saw the Emperor Charles (Lothaire Bluteau) offer lands and titles to Ragnar's brother Rollo (Clive Standen) as Ragnar reveals that he knows Floki (Gustaf Skarsgård) killed Ragnar's friend and confidante Athelstan (George Blagden). The season 4 trailer for Vikings, revealed at this year's San Diego Comic-Con, appears to place the upcoming ramifications of these acts front and center. Watch it above.
Next season's trailer centers on these betrayals, along with a few other power plays gearing up down the line. The voiceover intoned over the beginning - "Vanity of vanities..." - is from scripture, Ecclesiastes 1:2 to be exact, and suggests that Ragnar's ambition will soon overcome his good sense.
We also see Princess Aslaug (Alyssa Sutherland) apparently putting her own maneuvers in play, with the juxtaposition between her and Lagertha (Katheryn Winnick) suggesting that the question of just which woman will "one day" rule the land could remain up in the air until all the game pieces have been played.
History's only scripted series to date may play somewhat fast and loose with actual history, but what was once possibly seen as a cynical attempt to cash in on the Game of Thrones craze has drawn solidly high ratings throughout its run and gathered a loyal fanbase. However, while Ragnar Lothbrok is already a legend in Viking history, his television counterpart may yet face his biggest challenges.
Vikings will return for season 4 on History in 2016.