The popular historical drama television series, “Vikings,” on the History Channel, returned with its season four premiere this past Thursday.

Because there isn’t much historical proof or evidence of the Norsemen and their journeys, many historians have critiqued the authenticity of the show. Despite these claims, the show hasn’t been negatively affected from a viewership standpoint.

The “Vikings” series first premiered on March 3, 2013 and received six million U.S. viewers. In its first season, Metacritic gave it a score of 71. With each season, “Vikings,” has seen an increase in favorability in accordance with Metacritic. The second season jumped to a score of 77, and season three moved to 81.

Loosely based on journeys of the Scandinavian Norsemen and events of the 13th century, the first three seasons outlined the life of legendary Viking, Ragnar Lothbrok of Kattegat, a village of Scandinavia.

Beginning as a poor farmer, Ragnar opted to rebel against Earl Haraldson’s wishes and sail west to discover new land. Much to the Earl’s surprise, Ragnar discovered land and returned to Kattegat with treasure. After proving much of the village wrong, Ragnar ultimately challenged and defeated Earl Haraldson for control of Kattegat. From that point on, Ragnar and the Lothbrok family created a dynasty of Viking warriors to begin dominating many of their raids.

“Vikings’” first episode of season four, “A Good Treason,” set the stage for what’s to come.

After many raids, plot-twists and deaths throughout the first three seasons, the now King of Denmark, Ragnar, finds himself very ill and nearing death.

His son, Bjorn, fled Kattegat after the unauthorized arrest of Floki for the murder of Athelstan, Ragnar’s good friend and former monk. With Bjorn journeying into the wild to find himself, King Ragnar has a lot on his plate. Will he make the difficult decision to kill his former comrade, Floki, in front of the village of Kattegat?

Rollo, the brother of Ragnar, returned from Paris only to betray his former allies. He was left behind after the successful raid by the Norsemen. And in a surprising turn of events, Rollo was given an offer he couldn’t refuse: Becoming King of Paris. However, he had to agree to defend Paris providing that Ragnar returns. Rollo reluctantly accepted. Rather than wait on Ragnar and his Vikings to raid Paris, King Rollo sailed to Scandinavia to kill his former friends before they could get to him. One can only wonder if his next plan is to seek revenge on his brother.

Then there is Ragnar’s former wife, Lagertha, and current wife, Queen Aslaug. Both are determined to achieve great things while holding positions of power. Lagertha has regained her power as an earl of Hedeby, while Queen Aslaug has aspirations of ruling Kattegat if death seeks sickly Ragnar.

Though King Ragnar’s health seemed bleak in the season three finale, it now seems that Ragnar has found strength. Expect the unexpected throughout season four, as there are many mini storylines on the horizon.