Vikings is preparing for its sixth and final season, and a look back to the first seasons is inevitable, which raises the question: why did Travis Fimmel leave the series? Created by Michael Hirst, Vikings premiered in 2013 on the History Channel. Originally planned to be a miniseries, the show proved to be quite successful and was renewed for a second season a month after its premiere.

Vikings recounts the adventures of Ragnar Lothbrok, the legendary Norse hero who is said to have been a descendant of Odin, and his Viking brothers from the start of the Viking Age (marked by the Lindisfarne raid, depicted in season 1) onward. Ragnar was the main focus of the first season, with the following seasons focusing more on his sons and their adventures in England, Scandinavia, and the Mediterranean. Still, Ragnar was a big presence in the series up until season 4, when Fimmel left Vikings and Ragnar Lothbrok ascended to Valhalla. But why did he leave?

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So although Vikings was renewed thanks to positive reception, Hirst once told Variety that Fimmel knew Ragnar was not going to be around for long. When Fimmel was cast, all there was were the first scripts and the bible for the first season, in which Ragnar dies at the end. Vikings was going to be a one-season job for Fimmel, but it became much more thanks to the potential of the story and his performance as Ragnar, though that didn’t mean he was going to stay for the entire series' run. Ragnar set the stage for his sons to be the main focus of the rest of Vikings; his arc came to an end in season 4, and so, Travis Fimmel left Vikings.

Ragnar died in part 2 of season 4 when he was thrown into a pit of venomous snakes in the episode “All His Angels”. Because of this, season 5 followed the adventures of his sons, although Fimmel made a surprise return as Ragnar in a vision where he asked his son Björn (Alexander Ludwig) what he was fighting for. Since his departure from Vikings, Fimmel has appeared in a couple of films, such as Lean on Pete, Finding Steve McQueen, and most recently Dreamland, alongside Margot Robbie and Garrett Hedlund. He’s also set to appear in Ridley Scott’s drama series Raised by Wolves.

Unlike many other TV series where one of the lead actors leaves due to creative conflicts or for personal reasons, in the case of Travis Fimmel and Vikings it was all because Ragnar Lothbrok’s time in the story had come to an end. Ragnar might not have been initially intended to survive past the first season, but his presence was what made the series so big and made it possible for other characters to continue with it.

Next: What To Expect From Vikings Season 6