I already knew about this. Can you provide any information about the name's background?
The name come from an old West Slavic Tribes called "Kujawianie" in Polish. I guess it would just be "Kuyavians" in Anglicized form. They were located and set up towns, grody, in what is now Kujawy. My guess is that they got absorbed with the Christianization of Poland. Though, as the region's name indicates, their identity didn't vanish completely.