: To ensure the gods' favor, Queen Lagertha performs a human sacrifice in Kattegat before the fleet sets sail.
, titled " Revenge ," is a pivotal chapter in the series where the sons of Ragnar Lothbrok finally exact their vengeance upon King Aelle of Northumbria. Episode Details Original Air Date : January 18, 2017 Director : Jeff Woolnough Writer : Michael Hirst Major Plot Points : To ensure the gods' favor, Queen Lagertha
: In direct retaliation for Ragnar’s death in the snake pit, the sons of Ragnar capture Aelle and subject him to the brutal " Blood Eagle " execution. : After the death of Ragnar, his sons—Bjorn,
: After the death of Ragnar, his sons—Bjorn, Ivar, Ubbe, Hvitserk, and Sigurd—assemble a massive Viking force in Kattegat. Tensions arise between Bjorn and Ivar over who will lead the army. Cast List for Episode 18 Vikings recap: Season
: King Ecbert tasks his son, Aethelwulf, with organizing the defense of Wessex as they realize the full scale of the Viking threat heading their way. Cast List for Episode 18 Vikings recap: Season 4, Episode 18 - Entertainment Weekly
: The Great Heathen Army lands on the shores of Northumbria. King Aelle, vastly outnumbered, attempts to defend his kingdom but his forces are quickly overrun by the Vikings.