Dr. Wayne Bartlett

was a Christian king at a time when Christianity was just being established in Norway and Scandinavia more generally.

He wasn't the first Christian king, but things had gone very much up and down.

And Olaf's perhaps greatest achievement, really, ironically, was when he was killed.

Because when Olaf died in battle, basically what happened fairly soon after is Olaf became a Christian saint.

And he's still patron saint of Norway to this day.

So they were half brothers.

They shared a mother, but not a father.

Both sons of a lady called Asta.

But Olaf's father was Harald Grenzke.

Harald's was a guy called Sigurd Sir, Sigurd the Pig, which is a very interesting nickname, to say the least.

So they were connected, but they had fairly separate lives for much of the time.

Though, ironically, Harald was there when Olaf was killed.

There was an age difference.

Olaf was probably a good 15 to 20 years older than Harold.

So they would have seen each other.

They would have spent time in each other's company, but very much their own people as well.

So during this great battle at Stiklestadt, Harald was there alongside Olaf.

Harald was only probably about 15 at the time, so pretty young, though not unknown in Viking times for someone in their mid-teens to become something of a warrior.

Olaf actually suggested to him, according to the sagas at least, that he shouldn't take part in the battle.

He was too young and Harald wasn't having that.