COPENHAGEN, Denmark (AP) — Vikings had windows — usually only associated with medieval churches and castles — meaning Norsemen dignitaries sat in rooms lit up by apertures with glass, Danish researchers said Thursday. The glass panes can be dated from long before the churches and castles of the Middle Ages with which glazed windows are associated, they said.

“This is yet another shift away from the image of unsophisticated barbaric Vikings swinging their swords around,” said Mads Dengsø Jessen, a senior researcher with the National Museum in Copenhagen.

Over the past 25 years, archeologists have found glass fragments in six excavations in southern Sweden, Denmark and northern Germany.

In Copenhagen, 61 fragments of glass panes have been analyzed and researchers concluded that the pieces of glass can be dated from long before the churches and castles of the Middle Ages and that Vikings had windows with glass panes between 800 and 1100. The Viking Age is considered to be from 793 to 1066.

“We only associated early window glass with the Middle Ages, therefore assuming that the glass could not originate from the Viking Age,” the National Museum said in a statement. The glass fragments “can be dated to the Vikings Age and most likely must have been in use in that time period as well,” said Torben Sode, a conservator with the museum who first connected the dots.

The museum said glass windows were for the upper echelons of society and religious use, as was the case in the rest of Europe. Dengsø Jessen said there may have been glass windows in the Vikings’ vast hall buildings. They were not large, transparent windows as we know them today, but probably smaller windows, possibly composed of flat pane glass in different shades of green and brown. The idea was not to be able to look out, but to create a colorful inflow of light into the building.

The museum said “it is most likely that the Vikings acquired (the glass) through trade.” The Norsemen known as Vikings undertook large-scale raiding, colonizing, conquest and trading throughout Europe. They also reached North America.

“In fact, we are talking about a cultivated Viking elite with royal power that equaled that, for example, of Charlemagne, king of the Franks. This is something that is often omitted in the simplistic Hollywood portraits of Vikings,” Dengsø Jessen said.