https://phys.org/news/2018-07-danish-cities-older-previously-thought.html

Odense is conventionally thought to have been established in the year 988 CE, according to written sources.

"They written sources show that Odense had a Bishop and a Cathedral, which suggests that it was already a large town at this point. So, there must have been something earlier," says Mads Runge, head of research at Odense City Museums, Denmark, and lead-author on the new study published in the Danish Journal of Archaeology.