The word berserk came into the English language in the early 19th century to describe an ancient Norse warrior who fought with uncontrolled ferocity (also known as a berserker).
The English word derives from the Old Norse berserkr (noun), itself probably from combining bjorn (bear) and serkr (coat). It could also possibly from berr ‘bare’ (i.e. without armour) and serkr.
For some reason, I always thought this was a word of Afrikaans origin, until I came across this story in Collingwood and Stefansson’s A Pilgrimage to the Saga-Steads of Iceland:
Two Swedes came out to Iceland in the train of a chief, and they were Berserks. From time to time they went mad like dogs…and feared neither fire nor steel. They were good at need but ill to do with between whiles, and nobody liked to have them on his hands. At last a certain Arngrim [Styr] gave them a home….
Of course one of them fell in love with Styr’s pretty daughter Asdis, but no damsel of high degree would marry a Berserk: and yet even Styr dared not say so. So he went to Helgafell for advice from Snorri the Priest, and coming back, bargained with them that they should do certain works for him and then he would think about their request.
So they reluctantly set about making him a road through the lava, and a boundary wall across it, and a ‘borg’…to protect cattle. On the day when the last stone was laid Asdis met them dressed in her gayest and sweetly listened to their songs of triumph. No wonder they were in high spirits – but when the Berserker fit went off it left them all fordone and weaker than common men. Then Styr asked the into his new bath-house to bathe after their toil. It was in the manner of Roman bath, with a furnace fed from without, a hot room, more or less underground,and a little ante-room, to which steps went down through a trap door – the bath commonly used by the vikings and no doubt imitated from the Irish. When they were safely in the bath, Styr fed the fire till it roared again and closed the trap door with a raw hide and great stone – and waited for the Berserks to be stifled. In spite of it all they burst the hatchway but one was knocked on the head and the other thrust back into the death-trap. Then they took the bodies out and buried them ‘in a dale so deep that one can see nothing from it but the sky above’ (78-9)
The Gerts are going to be very very careful not to go even a little bit berserk on their forthcoming trip to Iceland, especially when wallowing in hot baths.