Vinland Saga is a historical series set in 1013 AD, following Thorfinn and a group of Viking mercenaries as they attempt to take over England.
The series itself draws inspiration from the Vinland Sagas, which comprises two sagas, the Saga of Erik the Red, the Father of Leif Eriksson and the saga of the Greenlanders. Most of the characters from Vinland Saga are real, but their features have been heavily dramatised.
Vinland’s main character is based on the real-life Thorfin Karlsefni, who is one of the most famous explorers from the Norse region around the time the series takes place. Thorfin wrote a series of stories about his travels, which is what the series draws from.
Thorfinn’s father, Thors, is an anime-only character and does not appear to fight any conquests, at least at the time the series is set. A character inspires Thors in Norse Legends, known as Thord Horsehead. However, his name was shortened to Thors.
Leif is based on the historical Leif Erickson, an explorer credited in modern times with discovering the North American continent where Vinland is located.
Askeladd, the leader of the Vikings, is based on inspired by a Norse folklore character called Askelladden. But it's believed that Askellad was purely designed to act as a mentor character for Thorfinn. As a half-welsh, half-dane warrior, Askellad is meant to hint at the intermingling that happens from Viking raids.
Canute’s real-life equivalent was an actual Danish king. When initially introduced, Canute was mistaken as a woman, which reflects the real-life Canute who was meant to have beautiful looks. Cabyte is also known as one of the first Viking rulers to support Christianity, which plays a large part in the series. Canute was an exceptionally strong person, unlike what we have seen from the character so far.
Thorkell is probably one of the most accurately depicted characters in the series. Known in real life as Thorkell the tall, he was a feared warrior who defected to the English and fought against Canute before returning to his side and becoming one of his strongest generals. The only place where he falls short is his personality; the real Throkell was meant to be much more measured and calculating than the battle-hungry version seen in the series.