Viking researchers have found Allah's name embroidered onto ancient burial clothes found in 9th and 10th century graves in Sweden.
The "staggering" discovery was made after analysing materials originally thought to be ordinary examples of Viking Age decoration when they were found over 100 years ago.
The new investigation, by archaeologist Annika Larsson of Uppsala University, found woven silver and silk patterns with geometric Kufic script spelling the words "Allah" and "Ali".
Found in Viking boat graves at two separate sites in Birka and Gamla Uppsala in Sweden in the late 19th and mid-20th centuries, Larsson said that the designs, under 1.5cm (0.6in) high, were unlike anything she had seen in Scandinavia.
Larsson said that she became interested in the fragments after realising the material had come from central Asia, Persia and China and resembled Moorish designs.
She said she realised that the name "Ali" - the fourth caliph of Islam – and Allah on at least 10 of the nearly 100 pieces she is working through, and they always appear together.
The new find prompts questions about Islamic influence in Scandinavia which seems to extend more than just the plunder of Muslim lands.
"The possibility that some of those in the graves were Muslim cannot be completely ruled out," Larsson said.
"We know from other Viking tomb excavations that DNA analysis has shown some of the people buried in them originated from places like Persia, where Islam was very dominant.
"However, it is more likely these findings show that Viking age burial customs were influenced by Islamic ideas such as eternal life in paradise after death."
Geneticists will now assess the geographic origins of the bodies dressed in the funeral clothes to see if they were indeed Scandinavian natives.
A silver ring from a female tomb at Birka was found two years ago that found the phrase "for Allah" inscribed in Kufic, which was developed in the Iraqi town of Kufah in the 7th Century.
Larsson believes that the discovery is so interesting because it is the first time historic items mentioning Ali, cousin and son-in-law of the Prophet Muhammad, have ever been found in Scandinavia.