Age: 30-32 (Season 1) 33-37 (Season 2) 39 (Season 3)
Rhaenyra is 14 years old at the beginning of House of the Dragon and grows up to 18 during the first four episodes. Milly Alcock, the young Rhaenyra's actress, was 21 when HOTD season one began production.
Age: 32 (Season 1)
So if you're caught up with the show then Ragnar, Lagertha, Floki, Rollo, Ælla and the "original" crew are around 60. Björn and Judith around 40. The young and new cast around 20. Also Bjorn states that Harald conquered Rogaland(year 872 or even closer to year 900).
The Seer. Seiðr of Kattegat. A 200-year-old blind being who often provides mysterious predictions to the characters. He is murdered by Ivar after refusing to recognise Ivar as a god and predicting Ivar's fall.
Ragnar was born in 750, in Kattegat. They had one daughter: Gyda Lothbrok. They divorced. Lagertha passed away in 821, at age 58.
In the end, Floki didn't become the next Seer, and it's unknown if he truly had a connection to Loki, but the Seer licking his hand remains one of Vikings biggest mysteries.
Some viewers have taken Björn's age in season 1 as a reference to calculate Ragnar's age, as he's said to have become a father at the age of 19, and Björn is 12 years old at the beginning of the series (listed as being born in 781), which fits with the previous calculation.
Vikings - Ivar Isn't Afraid To Die And Walks ON HIS OWN [Season 5 Official Scene] (5x10) [HD]
The Vikings typically lived to be around 40-50 years old. But there are also examples of upper class Vikings who lived longer – for instance Harald Fairhair, who was King of Norway for more than 60 years. (Picture of King Harald from the 14th century Icelandic manuscript Flateyjarbók / public domain.)
It's generally assumed that Floki was more on the lines of schizophrenia due to his religious delusions and erratic manners, though some have suggested that he might have been autistic.
Ivar made a surprising decision in the Vikings series finale, sacrificing himself in order to save the life of his brother Hvitserk. He is then killed by a Wessex soldier during the show's last epic battle.
The events of 1066 in England effectively marked the end of the Viking Age. By that time, all of the Scandinavian kingdoms were Christian, and what remained of Viking “culture” was being absorbed into the culture of Christian Europe.
Rollo is Ragnar's older brother and was known as a fearsome Viking warrior with an impulsive streak and a lot of internal struggles, which often shone through his violent actions.
Ragnar is said to have been the father of three sons—Halfdan, Inwaer (Ivar the Boneless), and Hubba (Ubbe)—who, according to the Anglo-Saxon Chronicle and other medieval sources, led a Viking invasion of East Anglia in 865.
Ragnar the younger is around 10-12 years older than Uhtred, so he would be roughly 26 when his father is killed by Kjartan.
Ubbe. If Vikings had a hero, then it would be Ubbe. His power wasn't just in the sword or in the ax alone. It was his strong will to fight for the right thing.
Finally, that one-eyed stranger who arrived at the end of last week's episode appears again, confirming that he is Odin.
Ivar the Boneless (sort of) had a son in Vikings season 5, but left poor baby Baldur to die in the forest after seeing his facial deformity.
Ragnar Lothbrok's eldest two sons, Agnar and Eric, were allegedly killed in an attempt to make Sweden submit to Ragnar's rule. These two sons may or may not have existed; they only exist in one of the sagas discussing the life of Ragnar Lothbrok.
As the oldest son of Ragnar and the only surviving child of Ragnar and the famous shield-maiden Lagertha, Bjorn already has the makings of a great warrior. Both of his parents are well-known for their actions during battle, and their leadership outside it.
Saxo recounts that Ragnar was still annoyed with Lagertha for having set beasts on him, so he divorced her and married Thora Borgarhjört, the daughter of the king of Sweden. They had several children together.
Floki as Loki
Floki principally worships Loki and believes himself to be a descendant of the God. Ragnar notices that Floki is a lot like Loki, only not a god. King Horik and Floki quip over a story about Loki stealing a necklace that belonged to Freyja while in the shape of a fly.
Ragnar Lothbrok
On his way to his death, Ragnar realized that the driver of the carriage was blind, but later on, once in the pit of snakes, the last thing he saw was the robed figure of a hidden King Ecbert, who is believed to have been the “blind man” as he didn't see Ragnar's last move against him.
Long before Ragnar left for England and his final, snake-carpeted resting place, the seer told him that he wouldn't die until the blind man saw him.