When did history books change King Cnut to King Canute?

Question

When did history books change King Cnut to King Canute?

Answer 1

When Edmund Ironside died suddenly in 1016 AD. Sweyn's son took over the thrown of England. He was Cnut (Canute)

Cnut was a strong, if harsh , ruler who brought peace to England. He was also king of Denmark.

Answer 2

When I was at school in the 60s/70s we learned about "Canute" but subsequently studying archaeology and reading history I have usually seen him referred to as "Cnut" so I think it has relatively recently reverted. As to when he went from "Cnut" to "Canute" I would guess it was under the Victorians.