A researcher says he's finally deciphered an obscure Nordic code that had long stumped cryptologists, according to news reports.

The code was written with "runes," or letters in the runic alphabet, which dominated parts of northern Europe before the Latin alphabet was embraced. Vikings and Norse people writing in runes commonly used codes to jot short messages. These often-playful writings were scratched into sticks, wood, stones and other everyday objects, which have been found at archaeological sites across the region.

"They were used to communicate, like the SMSes of the Middle Ages — they were for frequent messages which had validity in the here and now," code-breaker and runologist K. Jonas Nordby told The Guardian.

Nordby pointed to examples like one secret message that says "Kiss me" written in cipher runes, the most common code of Scandinavia during medieval times. Other messages provide early lessons in swagger: "These runes were carved by the most rune-literate man west of the sea," says one inscription scrawled inside a Stone Age burial chamber Orkney Islands in modern-day Scotland, according to ScienceNordic.

The code Nordby cracked was called the jötunvillur code. To use it, message-writers had to swap out each individual rune with the last sound in the rune's name. For example, the rune for "m," called "maðr," would be replaced with the rune for "r," according to The Guardian. But these systems can become confusing because many of the names of the runes end in the same sound.

Nordby's breakthrough apparently came in the form of a 13th century rune stick uncovered at Norway's Bergen wharf, or Bryggen, a port founded in 1070 that's now a UNESCO World Heritage Site. The stick contained the names of two men, Sigurd and Lavrans, etched in both jötunvillur code and in standard runes. So far, has he has investigated nine runic messages written in the jötunvillur code.

Another rune expert, Henrik Williams, of Uppsala University in Sweden, told ScienceNordic that runic codes "challenged the reader, demonstrated skills, and testify to a joy in reading and writing."

But Williams himself didn't have such a high opinion of the jötunvillur code, calling it "idiotic." He told the news site "whoever made it chose a system that is so hard to interpret. It's irritating not being able to read it.”

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