Muslims use the word Allah for god, while Ali is the name of Prophet Muhammad’s cousin and son-in-law.
The Vikings could be influenced by Islam and "the idea of an eternal life in paradise after death," Annika Larsson, a researcher in textile archaeology at Uppsala University, told Anadolu Agency on Friday.
The words which appeared as ancient Arabic script’s Kufic characters were found in silk costumes in boat-graves as well as in chamber graves in Sweden's Birka, the historic Viking city.
"In the Quran, it is written that the inhabitants of paradise will wear garments of silk, which along with the text band’s inscriptions may explain the widespread occurrence of silk in Viking Age graves," the researcher said in an earlier statement.
Similar Kufic characters were also found in mosaics on burial monuments and mausoleums, primarily in Central Asia, the university said in a statement.
In 2015, Swedish researchers at Stockholm University also discovered a ninth century ring in a Viking grave with an inscription that says ‘for Allah’ or ‘to Allah’.